Browned Butter M&M Blondies

Start by browning the butter. You'll take ½ cup of butter and melt in a medium saucepan, and then continue to cook past the point of boiling. You will do this over medium heat, past the point of the butter foaming, until it turns a nice golden brown, and has a nutty smell. Make sure you are stirring and watching it, because it will turn from perfectly brown to burnt fairly quickly. Once finished browning, pour into a cup or bowl and allow to cool.
Preheat oven to 350 F, and line an 8x8 baking pan with cooking spray and parchment paper.
In a medium bowl, stir together browned butter and brown sugar until combined. Add egg, yolk and vanilla and mix until combined.
Stir in cornstarch, salt and flour. Then very carefully fold in m&m's and chocolate chips.
Pour into prepared baking pan and smooth with a spatula to make even for baking. Top with a few more m&m's and flaked salt.
Bake for 20-23 minutes or until light golden brown along the edges. Allow to cool before serving.