Preheat your oven to 350°F. Line a mini muffin pan with liners.

In a large bowl, beat the softened butter, brown sugar, and granulated sugar until light and creamy, about 2 to 3 minutes with a hand mixer on medium.

Mix in the egg and vanilla until smooth.

In a separate bowl, whisk together the flour, baking soda, and salt. Add the dry mixture to the wet ingredients and stir on low or by hand just until no dry flour remains.

Gently fold in the mini chocolate chips and ¾ cup mini M&Ms with a rubber spatula.

Scoop about 1 tablespoon of dough into each mini muffin cup so they are roughly ¾ full. Press the tops lightly to level. I used a cookie scoop to make this easier.

Bake for about ¾’s of the way (Around 8-ish minutes). The edges should not quite be set and maybe oh so slightly golden while centers still look a little soft.

Press a few extra mini M&Ms into the tops so they stick and look colorful.

Stick back in the oven to finish baking. You’ll know they’re done with the centers look more solid, but still soft. If everything starts turning a golden color, they’re definitely done, and you should take them out immediately.

Let the cookie cups cool in the pan another 10 to 15 minutes. Gently twist and lift each one out, then transfer to a wire rack to cool completely. Arrange on a platter and serve.