Preheat oven to 325 degrees.

In a microwave-safe bowl, melt the chocolate chips and butter together for about 45 seconds. Remove and stir, then, if needed, microwave for another 30 seconds, until it's completely melted. Stir together until combined.

Pour the chocolate mixture into a mixing bowl or stand mixer and whisk in the sugar, eggs, and vanilla until smooth.

Pour the flour, cocoa powder, baking soda and salt on top of the wet ingredients and mix just until combined.

Add in the M&M's and stir to evenly distribute (you may want to use a spoon or spatula to do this so your stand mixer doesn't crush the M&M's).

Line a cookie sheet with parchment paper or liners or lightly coat them with cooking spray, then drop the dough by tablespoonsfuls onto the sheet (give them about 2 inches of space, because they'll spread a lot).

Bake for 12-14 minutes, until the tops are puffed and cracked and dry-looking. Let them cool on the baking sheet for about 5 minutes before removing them to a cooling rack.

Enjoy!