Line the holes of the muffin tin with paper cases and set aside. Heat the oven to 160C/140C fan/gas 3.

Spread the walnuts out in a single layer on a baking tray and roast for 12-15 mins, or until fragrant and slightly darker in colour. Tip into a small food processor and blitz in 1-min bursts, scraping down the sides between each burst. When you have a buttery, mostly smooth paste, the walnut butter is ready – this may take 5-10 mins. You don’t want it to be completely smooth, as it will become too runny to fill the cups.

Melt the chocolate in a heatproof bowl set over a pan of simmering water, making sure the bowl doesn’t touch the water. Alternatively, do this in the microwave in 30-second bursts. Spoon 1 tsp chocolate into each case, then freeze for 10 mins before adding a spoonful of walnut butter. Push in a few pieces of chopped date, then spoon over the remaining melted chocolate. Freeze for at least another 30 mins, or until the chocolate is firm (the walnut centre will remain gooey), then transfer to a freezerproof container. Will keep frozen for up to a month.