Stir the melted butter, vanilla sugar and brown sugar.
Add the egg (it may look like there are two egg yolks in the photo but that’s just one egg that burst when I cracked the shell) and stir until smooth.
Mix in the flour.
Stir in the powdered coffee.
If using chocolate morsels, just stir them in. If using a block of chocolate, roughly chop or cut into small cubes, then stir into the batter.
Divide the batter between two microwave-safe ramekins. Microwave on HIGH, one at a time, for a minute and a half.
Then, dig in. Oh, wait! You might want to let the microwave chocolate chip cakes cool for a minute or two before digging in. Just to make sure you don’t burn your lips and your tongue.