Step 1

Preheat oven to 350ºF and line a 9x13 baking dish with parchment paper.

Step 2

In a large bowl mix together melted butter, brown sugar and vanilla. Then add in eggs and stir until batter is like a thick caramel.

Step 3

In a separate bowl, whisk together flour, baking soda and salt. Then pour flour into batter, roughly a ½ cup at a time, folding batter over itself to smooth any ribbons of flour into the batter. The batter will be very thick.

Step 4

Add in red and green M&M's and chocolate chips to batter and gently combine.

Step 5

Pour into baking pan and spread evenly. Top with additional M&M's and chocolate chips if desired. Bake at 350ºF for 26 minutes.

Step 6

Remove parchment paper from pan and set on a cooling rack to cool.

Step 7

Use a knife or bench scraper to divide into 24 squares.