In the bowl beat butter with brown sugar about 2 minutes. Break the eggs, vanilla, and beat together with the batter until slightly light about 2 minutes.

Mix flours with baking soda, cornstarch and shift it. Keep aside.

Mix flours into the wet batter, stir it well. Into the pan grease unsalted butter, put 40 grams batter. Press slightly, decorate with m&m chocolate chips. Bake with 400°F Fahrenheit about 15 - 20 minutes. Served it cold.