Melt 100 grams of cacao butter in a bowl over a pan of water on low heat.
Place 1 tablespoon of smooth peanut butter onto a microwave-safe dish and microwave for around 30 seconds or until runny. Stir the melted peanut butter into the cacao butter, then add the cacao powder, sugar and a pinch of salt.
Mix well until smooth and all the sugar has dissolved. Pour into mini chocolate moulds. Leave to set in the fridge for around 15 minutes.