The products that we need.

We are going to cook in the microwave. Divide the oil between two tall mugs, and then, using your finger to evenly smear the oil along the walls of the circles, excess oil to drain. Mugs must be well lubricated.

In a small bowl, whisk the egg with sugar, cocoa and sour cream.

On top of the chocolate mixture pour the baking powder and quickly stir.

Divide the dough between the circles and a little to knock the bottoms of the cups on a towel spread out on the table, o countertop to release any large air bubbles. Bake in the microwave one mug at a time. I have a power of 800 watts. The one I baked for exactly 1 minute.

The first time I advise you to set the time to 30 seconds and closely watch the cake. When the cake rises about half, another 15 seconds. The difference between soft, fluffy cake and a hockey puck is a few seconds, so you'll have to experiment to see what works for your microwave oven. You can do one without separating the dough, just increase the cooking time.

You can sprinkle with powdered sugar and serve with fruit or berries.