Preperation :

Place the grill at the center of the oven. Preheat the oven to 180 ° C (350 ° F). Line 12 muffin cups with paper or silicone boxes.

In a bowl, in a double boiler or in the microwave, melt the chocolate with the butter. Add the brown sugar and whisk for 1 minute. Add the eggs and whisk again for 1 minute. Add the flour and mix for 1 minute.

Divide the dough into the molds. Place a piece of Mars bar in the center of each brownie, pushing it a little into the dough, and place another on top.

Bake 14 minutes or until a toothpick inserted in the center of the cake, avoiding the bar, comes out clumped and not completely clean.

Let the brownies cool for about 2 hours before eating them.