Malted milk and caramel ice-cream pie

Butter and line the base (not the sides) of a 22cm loose-bottomed, deep tart tin with baking paper. To make the base, heat the butter in a small pan or the microwave until melted. Put the biscuits and 100g of the crushed Maltesers in a sandwich bag and crush with a rolling pin, or blitz in a food processor, until you get crumbs.

Tip into a bowl, pour over the melted butter, add a pinch of salt and mix until it looks like damp sand.

Tip the mix into the tin and press into the base and sides to make an even crust about 5mm thick. Smooth with the back of a spoon if needed, to even it out. Put it in the freezer until needed.

To make the caramel, heat the butter, sugar, and cream in a pan, continuously stirring until it starts to simmer. (Be careful not to touch the caramel as it will burn!). Simmer for 2-3 minutes until thickened slightly and glossy. There should be no grains of sugar in the bottom of the pan. Add a generous pinch of salt and leave to cool to room temperature.

Spoon the softened chocolate ice cream into the biscuit base, and smooth over. If the caramel has stiffened too much when cooling, whisk in a splash of milk to loosen it. Cover the chocolate ice cream completely with a layer of caramel and freeze for 1 hour.

Add 100g crushed Maltesers and the malted milk powder to the softened vanilla ice cream and fold in with a spatula or wooden spoon.

Add this to the pie, on top of the frozen caramel. Smooth over the surface and freeze again for at least 2 hours before serving.

10 minutes before serving, carefully loosen the pie from the tin around the edges with a knife. Sit the pie on a small bowl or can, and push the sides of the tart tin down, away from the pie. Slide it off the base onto a serving tray, and leave for 10 minutes at room temperature (or 30 minutes in the fridge) until the ice cream begins to soften.

Scatter over the remaining 100g crushed Maltesers, and cut into slices to serve.