Preheat the oven at 160C. Baseline and grease two equally sized sandwich tins. Add the sugar and the butter to a bowl and whisk until very fluffy and a pale cream.

Wisk the eggs in a mug with a fork and then add them gradually to the mixture with 1 tbsp of flour each time.

Add the rest of the flour and the baking powder to the mixture and fold it in gently.

Dissolve the coffee in the boiling water and add to the mixture still folding. Pour into baking tin.

Sprinkle a few chocolate chips over the batter

Bake for 30 minutes

Once baked, leave it to cool, cut into small pieces and serve