• 125 g (4½ oz) butter, at room temperature
• 100 g (3½ oz) caster sugar
• 100 g (3½ oz) soft brown sugar
• 1 egg
• 1 tsp vanilla extract
• 125 g (4½ oz) plain flour
• ¼ tsp sea salt
• 45 g (1½ oz) cocoa powder
• ½ tsp bicarbonate of soda (baking soda)
• 75 g (2½ oz) chocolate chips

Ice-Cream Filling

• 500 ml 17 fl oz) mint chocolate chip ice cream

Preheat the oven to 180°C (350°F) or 160°C (315°F) fan forced.

In the bowl of a standing electric mixer or using an electric hand mixer and large bowl, beat the butter and two sugars until light and fluffy, about 2–3 minutes. Add the egg and vanilla and beat until incorporated. Add the flour, salt, cocoa powder and bicarbonate of soda and mix until smooth, about 1 minute. The dough will be slightly sticky, but that is because this recipe makes very flat, chewy cookies.

Line two baking trays with baking paper. Spoon 1 heaped tablespoon of the dough on each tray, pressing down so that they are slightly flatter. You should have 20–24 cookies. Bake the cookies for 6 minutes and then swap the trays around. Cook for another 6 minutes or until set but soft in the middle.

Remove from the oven and let cool on the trays for 5 minutes. The biscuits won’t seem completely done and will be a little squishy, but they will finish cooking on the trays. Remove to a wire rack when set. They will keep in a covered container for 4 days.

Remove the ice cream from the freezer and let soften for a few minutes. Scoop one to two small balls of ice cream between two cookies and press to flatten. Place immediately in the freezer. When finished, cover the container of sandwiches and keep frozen until serving.