INGREDIENTS
1
Egg, large
4
Egg yolks, large
7/8 cup
Oats, old-fashioned
1/2 cup
All purpose flour
1/8 tsp
Baking powder
1/8 tsp
Baking soda
1
Filling
13 1/2 tbsp
Golden brown sugar, packed
1
Powdered sugar
1/4 tsp
Salt, generous
1/4 tsp
Salt
14 tbsp
Sugar
1 tsp
Vanilla extract
1
Vegetable oil spray, Nonstick
1
Oat cookie crust
1/2 cup
Butter, unsalted
6 1/2 tbsp
Heavy whipping cream
1 tbsp
Nonfat dry milk, powder
9 tablespoons (1 stick plus 1 tablespoon) unsalted butter, room temperature, divided