Preheat the oven to 350F, then line a baking sheet with parchment paper or silpat.
In a medium bowl, cream the butter and both sugars together. I did so using my spatula.
½ cup butter, ½ cup brown sugar, ¼ cup granulated sugar
Add in the vanilla and egg and mix everything is smooth and well incorporated.
1 egg, 2 teaspoon vanilla extract
Add in the dry ingredients over the wet ingredient mixture, starting with the flour, corn starch, baking soda, and salt. Stir just until combined.
1 & ⅓ cup flour, 1 tablespoon corn starch, ½ teaspoon baking soda, ½ teaspoon salt
Fold in the M&M's, and Oreo pieces then using a large cookie scooper (¼ cup- 4 tbsp), scoop our the cookie dough to create 10 equal cookies.
⅔ cup Valentine's day m&m's, 7 Oreo cookies
Place them on the prepared baking sheet and bake for 13 minutes. Don't worry if they look underdone or gooey in the middle. That's what we want, they will continue to bake even after you pull them out of the oven to cool. Use a larger cookie cutter to swish the cookies around as soon as they come out to make them perfectly round.
Cool on the cookie sheet for 5 minutes then transfer to a cooling rack.