Preheat the oven to 350° and place rack in middle position of the oven. Line two large baking sheets with parchment paper.
In a medium bowl, mix the flour, corn starch, cocoa powder, baking soda, and salt together. Set aside.
In the bowl of a mixer with the paddle attachment fitted, cream the butter, brown sugar, and granulated sugar together for 2 minutes on medium high.
Add the egg, vanilla extract, vinegar, red gel food coloring and mix until combined. Scrape down the sides of the bowl with a rubber spatula as needed.
Add the dry mixture and mix on low just until combined. Remove bowl from the mixer, and using a wooden spoon, fold in the white and semi sweet chocolate chips and the M&Ms. The dough should be thick, and a little difficult to fold!
Using a large cookie scoop, or an ice cream scoop, make 9 equally sized cookie dough balls, 5 and 4 on each cookie sheet. Roll each into an even ball.
Take each cookie dough ball, and pull it in half, then press the two pieces together, keeping middle split-side on the outside, then place on the lined baking sheet. Press down slightly with your fingers to flatten.
Bake one sheet of the cookies in the preheated oven on the middle rack for 9 minutes. Remove from the oven and drop the hot pan on the counter (from about 1 foot above) to de-fluff and slightly drop the cookies. Repeat 1-2 times. This is loud!
Let the cookies cool on the baking sheet just 1-2 minutes until you are able to move them to a cooling rack using a spatula. Repeat with the second batch of cookies.
Keep cookies in an airtight container at room temperature for 3-4 days.
