https://www.theguardian.com/food/2023/jul/24/budget-peanut-butter-cheap-recipes-shivi-ramoutar-west-african-stew-peanut-butter-cups?CMP=Share_iOSApp_Other
30g butter, plus a little extra for greasing
150g dark chocolate
50g peanut butter
6 digestive biscuits, blitzed or bashed to fine crumbs (put them in a food bag or tea towel)
A pinch of salt
Grease a 12-hole cupcake tray (or use a 24-hole mini cupcake tray). Melt the chocolate in short bursts on high in a microwave, stirring often. (You can also melt it in a heatproof bowl set over a pan of barely simmering water, making sure the base of the bowl doesn’t touch the water.) Leave to cool a little.
In a bowl, mix the butter, peanut butter and biscuit crumbs with a pinch of salt. Divide between the cupcake holes, pushing the mixture right down into them with the back of a spoon, and making each as level as possible.
Carefully spoon over the melted dark chocolate, then pop the tray into the freezer for two to three hours, until frozen solid. Pop out the cups from the moulds and enjoy, or store in a resealable bag in the freezer.