125g unsalted butter, chopped, at room temperature
½ cup caster sugar
1/3 cup brown sugar, firmly packed
1 teaspoon vanilla extract
¾ cup plain flour
2/3 cup self-raising flour
¼ cup cocoa powder
2 x 52g bars Rolo chocolate
Grease a 12-hole non-stick, mini muffin pan (2-tablespoon capacity).
Beat butter, sugars and vanilla in a small bowl of an electric mixer until fluffy. Beat in egg until combined. Stir in combined sifted flours and cocoa.
Roll level tablespoons of dough into balls. Place a ball into each pan hole. Using your thumb, make an indent in the centre of balls. Place a chocolate in each indent, reserving remaining for another use.
Place remaining dough balls over chocolates, pressing to cover and seal edges.
Cook in a moderate oven (180C) for about 12 minutes, or until just firm when lightly touched. Remove. Stand in pan for 10 minutes. Loosen edges before turning out.
Serve cookie cups warm.
TIP! Cookie cups are best eaten warm so the centre stays gooey, however they can be served at room temperature. Cookie cups can be made up to four days ahead. Store in an airtight container.