Step 1

Melt the butter and dark chocolate together in a small pan over a low heat, or in the microwave in 30-second bursts until smooth. Leave to cool for a few minutes. Line a square cake tin (that can fit in your air-fryer) with baking parchment.

Step 2

Heat the air-fryer to 160C. Whisk the eggs, sugar and a pinch of salt together using an electric whisk until thickened and creamy.

Step 3

Sift over the flour and cocoa powder, and pour in the melted chocolate and butter mixture. Using a spatula, gently fold everything together until evenly combined, then stir in the white chocolate chips.

Step 4

Pour the batter into the prepared tin and air-fry for 25-35 mins until set with a slight wobble in the centre. Leave to cool completely before cutting into squares.