For The Biscuit Base For The Caramel Filling For The Topping

1. Warm oven to 180C/160C fan/gas 4 and line a large baking sheet with baking parchment.
2. To make the base, blitz the oats in a food processor until they're like flour. Add the remaining ingredients and whizz together until it starts to clump. Put the mixture in a bowl and roll it into a log, then cut into 18 equal-sized rectangular bars, roughly 9 x 2cm. Place them on the prepared tray and use a small palette knife to smooth the tops and sides of each biscuit. Bake for about 10 minutes until they're lightly golden at the edges, then set aside to cool.
3. While that's cooling, put all the caramel ingredients into the food processor (no need to rinse it first) and blitz until it forms smooth, shiny clumps. Use a spatula to bring it together, then roll into 18 evenly-sized balls with your hands.
4. Once the biscuits are cool, squash the caramel onto them. Use your fingers to mould it into shape and smooth out any bumps, particularly around the edges (since these will show underneath the chocolate coating).
5. Melt the chocolate in a heatproof bowl set over a pan of simmering water – make sure the water doesn’t touch the bowl (otherwise, the chocolate might seize and go grainy). Carefully dip one of the caramel-coated biscuits into the chocolate, gently turning it with a small palette knife (use this to lift it out too). Use a spoon to drizzle over more chocolate to coat it fully. Let any excess drip back into the bowl, then carefully transfer the biscuit back to the lined tray.
6. Repeat with the remaining biscuits, then chill in the fridge for at least 30 minutes or until the chocolate has set. Store the biscuits in an airtight container in the fridge. They'll keep for five days.