3large eggs,divided (1 egg, 2 yolks, and 2 egg whites)
1 1/2cupsall-purpose flour
1/2cupsemi-sweet chocolate chips
1cupchopped nuts(I left these out)
1cuplight brown sugar
Preheat oven to 350 degrees F. Grease a 9x13 pan and set aside.
In the bowl of a stand mixer, beat together butter and granulated sugar until creamy. Beat in 1 whole egg and 2 egg yolks (put aside the whites for later.) Beat in the vanilla extract.
In a separate medium bowl, whisk together the flour, salt, and baking powder. Add the dry ingredients to the wet ingredients. Blend until just combined. Spread mixture into 9x13" pan. Sprinkle with marshmallows, chocolate chips, and nuts-if using.
Beat egg whites until stiff peaks form. Gently fold in the brown sugar. Spread mixture evenly over marshmallows and chocolate chips. Bake for about 30 minutes or until bars are a deep golden brown. Let bars cool completely. Cut into squares and serve.