Step 1

Preheat the oven to 175 ° C (conventional heat).

Step 2

In a large bowl, mix the butter with the sugar and vanilla extract. Beat until the mixture is creamy. Add the eggs one at a time while continuing to beat. Add the milk.

Step 3

In a separate bowl, mix the flour, baking powder and a pinch of salt. Gradually stir the flour into the liquid mixture.

Step 4

Divide the batter in half. Melt the chocolate in a double boiler and add it to one of the two doughs. Add the cocoa. Mix well.

Step 5

Grease a cake tin or line it with baking paper. Pour in ¼ part of the vanilla batter, then ¼ of the chocolate batter, continue in this way, alternating colors. Finally, stick the tip of a knife into the cake tin and draw an S shape. This will make a nice pattern after baking.

Step 6

Bake for 45 minutes. Cover with foil if the cake starts to darken. Check with a knife to see if it is cooked through and put it in the oven for another 5-10 minutes if necessary.