Preheat oven to 350F and line an 8x8 inch pan with parchment paper.
Whisk together the oats, flour, baking powder, baking soda, salt, and cinnamon. Set aside.
255 grams old fashioned rolled oats, 313 grams all purpose flour, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon fine sea salt, 1 tablespoon ground cinnamon
Separately, whisk together the melted butter, brown sugar, and granulated sugar until combined.
226 grams unsalted butter, 250 grams light brown sugar, 100 grams granulated sugar
Add the eggs and vanilla extract and whisk to combine.
2 eggs, 1 tablespoon vanilla extract
Add the dry ingredients to the wet ingredients and fold until the flour is almost incorporated. Add the M&Ms and chocolate chips and fold through.
200 grams regular M&Ms, 130 grams mini chocolate chips
Press the dough evenly into the prepared pan and bake for 25-30 minutes until set and the tops are lightly golden.
Let cool for 20 minutes in the pan to enjoy slightly warm or let cool completely in the pan. Slice and enjoy!