Homemade Reese's Peanut Butter Cups

Bahan-bahan (30 porsi)

• 1 cup / 250g smooth peanut butter
• 60 g / 4 tbsp unsalted butter
• 1/4 cup / 55g brown sugar
• 1 cup / 120g icing sugar (powdered sugar) (see notes)
• 500 g /16 oz chocolate (for melting, not eating chocolate)