Begin by adding your granulated sugar and light brown sugar into a large bowl. Whisk together until combined and break up any large lumps. Add in your melted, room temperature unsalted butter and vegetable oil and whisk until combined. Add in your vanilla and whisk until combined and then add in your eggs, mixing well after each addition. Set aside.

Combine all your dry ingredients in a separate bowl and whisk to combine. Add the dry ingredients to the wet ingredients. Add your chopped chocolate and m&m's and use a rubber spatula to fold in gently until just combined. Be sure not to overmix or you will have dry brownies and no one wants that!