Dark Chocolate Peppermint M&M Cookies

1. Preheat the oven to 325°F. Line baking sheets with parchment paper.
2. In a large bowl, combine all purpose flour, cocoa powders, baking soda, and kosher salt. Use a whisk to stir, evenly distributing the dry ingredients and aerating the flour at the same time. Set aside.
3. In a large measuring cup, melt together 4 oz (1 stick or 1/2 cup) butter and chocolate in the microwave, heating 30 seconds at a time. After 30 seconds, stir the butter and chocolate together, then heat again. Stir after each increment until butter and chocolate combine easily. Do not overcook. Set aside to slightly cool.
4. In the bowl of a stand mixer or a large mixing bowl, mix the remaining 4 oz of butter together with granulated sugar, scraping the bowl often. Add eggs, one at a time, mixing on medium speed after each addition. Continue to scrape the sides of the bowl often.
5. Add vanilla to the mixture and mix on medium speed again until the wet ingredients are well combined. Leave the mixer on low speed and slowly add in the chocolate-butter mixture. Add it slowly so as not to accidentally 'cook' the eggs with the warm chocolate.
6. When chocolate has been completely incorporated, begin to add the dry ingredients in increments, mixing on low speed after each addition.
7. When a cohesive dark chocolate dough has formed, be sure to scrape the sides and bottom of the bowl to get any remaining flour and mix again, then remove from the stand mixer if using one.
8. Add both types of M&Ms and white chocolate chips to the dough, mixing them through by hand.
9. Use a medium sized cookie scoop to distribute 6-8 dough balls per baking sheet.
10. Bake each tray for 12-14 minutes. Remove from the oven. The cookies will be puffy. If you want the cookies to be flat like you see in the photo, immediate press each cookie with the flat back of a spatula, then allow to cool.
11. Cool the cookies on the baking tray for a moment, then move them to a wire rack to cool completely.