- 3 cups rolled oats
- 1 teaspoon salt
- 1/2 cup all-purpose flour
- 8 ounces butter, softened
- 1 cup packed light brown sugar
- 3 tablespoons melted butter
Preheat the oven to 350° F. Combine rolled oats, salt, and flour in the bowl of a food processor. Grind the mixture until the oats are broken into small pieces, about 20 seconds. Set aside.
Cream 8 ounces butter and brown sugar in a stand mixer with a paddle attachment or with an electric beater until light and fluffy, about 4 minutes. Add the dry ingredients and mix on low until blended.
Spread the mixture in an even layer over a parchment lined sheet tray, stopping 1 inch before the edges. Bake for 10 minutes, rotating halfway through.
After 10 minutes, remove the pan from the oven. Break up the mixture using a spatula, stirring it up so the golden brown exterior and the lighter interior are mixed. Re-spread the mixture evenly over the sheet tray, and return to the oven for an additional 10 minutes, rotating halfway through, until the top is golden brown.
Allow the pan to cool. Break up the crust into pieces and place them in the bowl of a food processor and process until homogeneous and mealy. Slowly pour 3 tablespoons of melted butter into the food processor through the top feeder tube as it's running. The mixture will feel slightly damp.
Pour the mixture into a pie plate and press the crust into shape on the edges and bottom. Chill for 20 minutes before filling.