First, melt the butter in the microwave until melted. Pour the hot butter into a large bowl. Let it sit for 15-20 minutes until the butter is room temperature.
1 cup Unsalted butter
In a separate bowl, sift the flour. Add in baking powder, baking soda, and salt. Set aside.
2 ¾ cups All-purpose flour, ½ teaspoon Baking soda, ½ teaspoon Baking powder, 1 teaspoon Salt
Using the bowl with the butter, add in brown sugar and sugar. Use a rubber spatula to mix. Add in vanilla and eggs. Mix until combined.
1 ¼ cup Brown sugar, ¾ cup White granulated sugar, 1 teaspoon Pure vanilla extract, 2 Large eggs
Pour the flour mixture into the wet ingredients. Fold the batter until it is combined. Add in the mini M&M's and mini chocolate chips and fold it in.
1 ¼ cup Mini M&M's, ½ cup Mini chocolate chips
Line two cookie sheets with parchment paper. Use a large cookie scoop (a 3oz cookie scoop) to scoop the dough. Place 6 cookie dough balls per cookie sheet.
Place the 1st cookie sheet that will be going in the oven, into the freezer for at least 10 minutes until the dough balls are cold. Place the rest of the cookie dough balls in the fridge.
Preheat the oven to 350°F. Bake one cookie sheet at a time. Bake for 13-15 minutes until the edges are golden brown.
Top the cookies while hot with extra mini M&M's and mini chocolate chips. Let the cookies sit on the hot pan for 5 minutes before transferring to a cooling rack.