Chocolate Rocky Road Slice
A no-bake traybake packed with oats, walnuts and coconut, bound with chocolate and golden syrup.
Allergens: contains cereals containing gluten, milk, tree nuts. Brands differ, so always check the labels on what you buy.
Per serving (approx.): 20g carbs · 12g sugars · 2g fibre. Estimates for carb counting, not medical advice. If you have diabetes, follow your GP or dietitian's advice.
Not every ingredient has a checked price at Aldi, Lidl, Asda, Morrisons, Iceland, so they aren't compared here.
Ingredients and prices
Swipe the table to see every supermarket.
| Ingredient | Tesco | Sainsbury's |
|---|---|---|
| Milk chocolateuse 100g | £1.19100g · £1.19 per 100g | £2.00180g · £1.11 per 100g |
| Milk chocolate chipspack 100g · use 100g | £1.19£1.19 per 100g | £1.25£1.25 per 100g |
| Golden syrupuse 4 tbsp | £1.80700g · £0.26 per 100g | £2.05750g · £0.27 per 100g |
| Unsalted butterpack 250g · use 125g | £1.85£0.74 per 100g | £1.85£0.74 per 100g |
| Walnutsuse 100g | £2.25200g · £1.13 per 100g | £1.90100g · £1.90 per 100g |
| Desiccated coconutuse 100g | £2.10200g · £1.05 per 100g | £2.70250g · £1.08 per 100g |
| Porridge oatsuse 250g | £1.45270g · £0.54 per 100g | £1.251kg · £0.13 per 100g |
| Basket total (full packs) | £11.83 | £13.00 |
| Cost of what this recipe uses | £7.04 | £6.81 |
| Per serving | £0.59 | £0.57 |
From your cupboard
Not in the prices above. Check you have these before you start.
Prices checked on 3 October 2026 from each supermarket's own listing or a price-comparison site. Each shop's unit price (or pack size) is shown under its price, and "cost of what this recipe uses" compares like with like (tap a price to see its source). Cheapest in each row is ticked. Prices, offers and pack sizes change; loyalty-card prices are not included unless stated.
Method
The method is written for 12. For a different number, use the amounts in the table above.
- Preheat your oven to 180C (160C fan, gas 4). Lightly grease a 20cm square baking tin with a little extra butter and line the base and sides with baking parchment, leaving a slight overhang to help you lift the slice out easily once it has cooled.
- Place 100g walnuts on a secure chopping board and use a sharp knife to roughly chop them into small, pea-sized pieces. Ensure the pieces are relatively uniform so they distribute evenly through the oat mixture without leaving large gaps in the final slice.
- Put 125g unsalted butter, 4 tbsp golden syrup, and 100g milk chocolate (broken into small squares) into a large saucepan. Place the pan on the hob over a low heat to ensure the chocolate melts gently without burning or becoming grainy.
- Stir the mixture constantly with a wooden spoon for about 4-5 minutes. It is ready when the butter and chocolate have completely melted together into a smooth, glossy, liquid brown sauce with no solid lumps of chocolate or butter remaining.
- Remove the pan from the heat immediately to prevent the syrup from overcooking. Tip in 250g porridge oats, 100g desiccated coconut, and the chopped walnuts, then stir vigorously until every single oat is thoroughly coated in the chocolate mixture and no dry patches remain.
- Transfer the chocolate oat mixture into your prepared baking tin. Use the back of a large metal spoon to press the mixture down very firmly into the corners and across the surface until it is flat, level, and tightly packed together.
- Scatter 100g milk chocolate chips evenly over the top of the surface. Bake in the centre of the oven for 15-20 minutes until the edges are starting to turn a deep golden brown and the centre feels slightly set but still has a little give.
- Remove from the oven and allow to cool completely in the tin for at least 1-2 hours. Once cold, lift the block out using the parchment paper and use a sharp knife to cut it into 12 even rectangular slices before serving.
Tips
- To make this recipe cheaper, you can swap the walnuts for an equal amount of raisins or sunflower seeds. Ensure you use standard porridge oats rather than jumbo oats, as the smaller flakes help the slice bind together more effectively.
- Cool any leftovers and place them in an airtight container in the fridge or freezer within 1-2 hours. Eat fridge leftovers within 48 hours (2 days); if frozen, defrost in the fridge and eat within 24 hours. If reheating, ensure it is steaming hot throughout and reheat only once.
Nothing wasted: your leftover ingredients
Supermarkets sell set pack sizes, so you'll have some ingredients left. Here's how to keep them, and other recipes here that use them up.
- Golden syrup · about 317g left
Check the label: most raw ingredients can be frozen before their use-by date, and cupboard staples keep for months. Use it in: Golden Syrup Flapjack Bars, Coconut Macaroons, Fudgy Milk Chocolate Brownies. - Unsalted butter · about 125g left
Check the label: most raw ingredients can be frozen before their use-by date, and cupboard staples keep for months. Use it in: Banana muffins, Ginger Cake, Pad Thai with Chicken. - Desiccated coconut · about 150g left
Check the label: most raw ingredients can be frozen before their use-by date, and cupboard staples keep for months. Use it in: Coconut Macaroons. - Porridge oats · about 750g left
Dry stores keep for months sealed in the cupboard, so nothing goes to waste. Use it in: Overnight Oats with Fruit and Nuts, Flapjacks, Apple Crumble.
Storing leftovers
Cool leftovers and put them in the fridge or freezer within 1–2 hours. Eat fridge leftovers within 2 days, or freeze them. Defrost in the fridge and reheat only once, until steaming hot all the way through (Food Standards Agency guidance).