In a large bowl using a stand or hand mixer, cream together butter, granulated sugar and brown sugar.
1/2 cup unsalted butter, 1/2 cup granulated sugar, 1/3 cup light brown sugar
Add egg and vanilla, mix until well combined.
1 large egg, 1/2 teaspoon pure vanilla extract
Add dry ingredients to wet ingredients and mix until just combined. Add chopped candy bars and M&Ms and stir until combined. If you feel like the dough has gotten too warm, wrap it in plastic wrap and toss it in the fridge for a few hours to let it firm up again. Okay, don't actually toss it - you might knock a carton of milk over or something.
Using a medium-sized cookie scoop, place dough onto prepared baking sheet an inch apart.
Bake for 12 minutes, or until the edges start to turn gold.
Let cool on baking sheet for a few minutes, then move them to a cooling rack to cool completely. Enjoy!