Cream butter and sugar together until light and fluffy, about 3-4
2. Mix in egg and vanilla extract.
3. Add flour, cocoa and baking soda and mix until combined.
4. Stir in chocolate chunks and M&MS. Dough will be thick and
5. Chill for at least 3 hours or overnight.
6. When ready to bake, preheat oven to 350 degrees.
7. Place parchment paper in the bottom of your cake pan to help
the cookie not stick. Grease the sides.
8. Spread the dough out into the cake pan. Bake for 18-20 minutes.
9. Remove from oven and let cool for about 15 minutes, then
carefully transfer to cooling rack to cool completely.