No Bake Rocky Road Recipe with Digestive Biscuits

I make rocky road at work in a school kitchen, in gastronorm trays, on a scale you would never need at home. This is the same recipe, worked back down to a batch that fits a normal tin: digestive biscuits, real butter, dark chocolate, golden syrup and mini marshmallows, all melted together and set firm in the fridge.

The one thing I do differently to most rocky road recipes is the marshmallows. They go into the pan with everything else and melt right in, rather than being folded through whole at the end. There is no marshmallow chunk in a slice of mine, just an even, slightly chewy set running all the way through.

There is no oven in it anywhere. You melt, you stir, you press it into a tin and the fridge does the rest, which is the reason a batch of it can go out to a few hundred children without tying up an oven anyone else needs.

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PPin it

Rocky Road, Ice Cream or Fudge?

Worth saying early, because the name means two different things depending on where you are standing. In Britain and Australia, rocky road is this: a no bake traybake of broken biscuit and marshmallow set in chocolate, cut into squares or fingers. In the United States the same name usually points at the ice cream flavour first, or at a fudge or a candy bar made with marshmallow and nuts.

They are not versions of one another. The ice cream is a frozen dessert, the fudge is a boiled sugar confection, and this is neither. If you came here after a tub of ice cream, this is not going to give you one.

The British version is also where the digestive biscuit comes in, and that is the part US readers usually have to translate. A digestive is a semi sweet wheatmeal biscuit, and graham crackers are the closest thing on an American shelf. Nuts are optional here rather than assumed, which is the other way round from most American rocky road.

The Marshmallow Goes In Melted, Not Folded Through

A marshmallow is mostly sugar syrup held up by a small amount of gelatine, and gelatine melts at a much lower temperature than the pan of butter and chocolate it is going into. So when a mini marshmallow goes into that pan, it does not just soften, it dissolves completely and becomes part of the mixture.

Fold whole marshmallows through a cooler mixture, which is how most recipes do it, and they stay as soft, gooey pockets you can see when you cut a piece. Melt them straight in, and the gelatine sets again once the mixture is chilled, but now it is spread evenly through the whole slab rather than sitting in separate lumps. That is the difference: an even chew throughout, rather than pockets of marshmallow between the biscuit and the chocolate.

The butter matters here too. Melting it into the chocolate rather than keeping the two separate is why this sets firm and fudgy in the fridge but never turns hard and glossy the way a bar of tempered chocolate does. That is normal for rocky road, not a fault: it is exactly why it needs the fridge to hold its shape.

Where This Recipe Comes From

The recipe I work from at school is written for gastronorm trays: eight kilos of digestive biscuits at a time, and the rest in proportion. Everything on this page is that same recipe divided down, with the ratio left exactly as it is, because the ratio is the part that has been tested on a few hundred portions at a time rather than the quantities.

That ratio is richer in butter than most rocky road recipes you will find, and it is deliberate. It makes a softer, fudgier slab that cuts cleanly straight out of the fridge and does not shatter when a knife goes through it, which matters a great deal more when you are cutting a full tray into portions than when you are cutting sixteen bars at home. It tastes the same either way.

Which Chocolate to Use

I use dark chocolate at 70% cocoa, and the reason is the set rather than the taste. Milk chocolate carries less cocoa butter and more milk solids and sugar, so it sets softer and with less snap to it than a dark chocolate does.

That matters more here than it would in most recipes, because this mixture is already being pushed towards soft. There is 250 g of butter in it, and butter melted into chocolate gives you something closer to a firm ganache than to a set bar of chocolate. Starting from a firm 70% is what keeps the finished slab cuttable rather than sticky.

You can use milk chocolate, or half and half, and plenty of people do. Expect a sweeter bar and a softer set, and keep it in the fridge rather than a warm kitchen.

A Closer Look at the Ingredients

• Digestive biscuits. Broken into a mixture of sizes rather than crushed to crumbs, so you get proper bite alongside the chocolate. Instead: in the US, graham crackers are the closest thing to a digestive.
• Butter. Real butter, not a spread or margarine. A spread carries more water in it, and that water is what keeps the set softer and stops the slab firming up properly in the fridge.
• Dark chocolate, 70% cocoa. The main structure of the bar. A high cocoa content sets firmer than a sweeter, milkier chocolate would. Instead: a mix of dark and milk chocolate works, just expect a softer set and a sweeter result.
• Golden syrup. Keeps the mixture smooth and glossy rather than turning grainy as it cools. Instead: light corn syrup, if you are in the US and cannot find golden syrup.
• Mini marshmallows. These melt completely into the hot mixture rather than staying as visible chunks, which is what gives the finished bar its even, chewy set.
• Icing sugar. A light dusting over the top once it is cut, purely for the look of it. Instead: leave it off altogether, it changes nothing about the bar underneath.

Equipment You Will Need

How to Make Rocky Road, Step by Step

1. Line the tin. Grease a 20 x 30 cm tin and line it with baking paper, leaving some hanging over the sides. That overhang is what lets you lift the whole slab out in one piece once it has set, rather than having to dig the corners out with a knife.
2. Break the biscuits. Put the digestive biscuits in a food bag and bash them with a rolling pin into a mixture of sizes, some fine crumbs and some proper chunks. Do not aim for even crumbs: the mixture of sizes is what gives the finished bar its bite, rather than a uniform sandy texture.
3. Melt the butter, chocolate, syrup and marshmallows. Put the butter, dark chocolate, golden syrup and mini marshmallows into a large saucepan over a gentle heat. Stir more or less constantly as it melts and keep the heat low, because chocolate left sitting over a high heat catches on the base of the pan and turns bitter. Keep your pan and spoon dry as well, since a splash of water is what makes melted chocolate stiffen into a paste. Keep going until the marshmallows have completely disappeared into the mixture and everything is smooth, with no marshmallow piece left anywhere in the pan.
4. Stir in the biscuits. Take the pan off the heat and tip in the broken biscuits. Stir until every piece, big and small, is coated in the chocolate mixture. Working off the heat here stops the biscuits softening any further than the coating itself does.
5. Press into the tin and chill. Pour the mixture into the lined tin and press it into an even layer right into the corners. Chill for at least 2 hours, or leave it overnight if that suits you better. It needs to be properly cold and firm before you try to cut it.
6. Cut and dust. Lift the set slab out of the tin using the overhanging paper. Dust the top with icing sugar, then cut into 16 bars using a knife warmed under hot water and dried between cuts, which gives you a clean edge instead of a crumbled one.

Recipe Card for Rocky Road

What Goes Wrong, and Why

There is not much that goes wrong with rocky road, which is part of why it gets made in school kitchens. The few things that do are worth knowing, because two of them get blamed on the wrong cause.

Seizing is when melted chocolate suddenly stiffens into a thick, dull paste. It is caused by a small amount of water getting into it, not by heat. Water wets the sugar and cocoa particles just enough to glue them to each other, and the whole thing turns from fluid to paste. A wet spoon, a splash from the tap, or steam from a pan underneath a bowl will all do it. The odd thing about it is that more liquid is the cure: stir in more warm liquid and the paste loosens back into a thick fluid. This recipe is harder to seize than most, because the butter and syrup are in the pan from the start rather than being added to bare melted chocolate.

Scorching is the separate problem, and that one is heat. Chocolate left over a high heat catches on the bottom of the pan and turns bitter and grainy, and there is no saving it once it has. Gentle heat and constant stirring is all it takes to avoid.

Not setting is almost always the fat. A spread or a soft margarine in place of butter brings water with it, and that water keeps the mixture softer than it should be, so the slab never firms up properly. The other cause is simply a warm kitchen: this sets with butter and chocolate rather than tempered chocolate, so it needs the fridge in a way a bar of chocolate does not.

Storing It

Keep it in an airtight container somewhere cool, and it holds well for about a week. If your kitchen runs warm, the fridge is the safer place for it, since the set is butter and chocolate rather than tempered chocolate and will soften faster in the heat than a proper bar of chocolate would.

Having It

It cuts small, so I treat it as something to have alongside a coffee or to pack into a lunchbox rather than a whole dessert on its own.

FAQ for Rocky Road

What can I use instead of digestive biscuits?

In the US, graham crackers are the closest match. Shortbread, rich tea biscuits or even Oreos also work, though each changes the flavour and how sweet the finished bar is.

What can I use instead of golden syrup?

Light corn syrup is the closest substitute if you are in the US and cannot find golden syrup. Honey or maple syrup will also set it, but both bring their own flavour along with them.

Can I fold whole marshmallows through instead of melting them in?

Yes, and it is how most recipes do it. Stir the biscuits and melted chocolate mixture together first, let it cool slightly, then fold whole mini marshmallows through at the end so they stay as soft pockets rather than melting. You will end up with visible marshmallow chunks in each bar instead of the even, chewy set my method gives.

Does it freeze?

I have not tested it myself, and recipes disagree on this: some say it freezes well for months, others say it comes out grainy once thawed. If you want to try, wrap a piece well and test one before freezing the whole batch.

Why did my melted chocolate go stiff and pasty?

That is seizing, and it is water rather than heat. A wet spoon or a splash from the tap is enough to do it. Stir in a little more warm liquid and the paste usually loosens back into a thick fluid. If it went bitter and grainy instead, that is scorching from too high a heat, and there is no fixing that one.

What can I use instead of marshmallows?

Nothing that does the same job, I am afraid. The marshmallow is what gives the set its chew, so leaving it out gives you a plain chocolate biscuit traybake instead, which is a good thing in its own right but not rocky road. Vegetarian and vegan marshmallows melt in the same way if you need them.

Can I use milk chocolate instead of dark?

Yes. It sets softer and sweeter, because milk chocolate carries less cocoa butter and more sugar and milk solids than a 70% dark does. Keep it in the fridge and it cuts fine.

Can I add nuts?

Yes, a handful of chopped nuts stirred in with the biscuits works well if you want them. Mine has none in it, but plenty of published rocky road recipes include them by default.

A Few Words from the Chef

This is what I make at work, just at a scale nobody needs in their own kitchen. Real butter and melting the marshmallows right in are the two things I would not change. Let me know in the comments how yours turns out.