- 1 1/2 cups old-fashioned rolled oats
- 3/4 cup whole wheat flour
- 1/2 cup Grape-Nuts cereal
- 1/2 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 12 tablespoons unsalted butter, cut into 12 pieces
- 1 cup packed dark brown sugar
- 1 large egg, lightly beaten
- 1/2 teaspoon vanilla extract
- 1 1/4 cups frozen blueberries
Adjust oven racks to upper third and lower third positions and preheat oven to 350°F. Line 2 baking sheet with parchment paper.
Toast oats in large skillet over medium-high heat, stirring occasionally, until fragrant, 6 to 8 minutes. Transfer to medium bowl. Stir in flour, Grape-Nuts, baking powder, baking soda, and salt. Set aside.
Wipe out skillet. Melt butter over medium heat. Cook until browned, 6 to 8 minutes, occasionally swirling pan. The butter will foam during cooking; subsiding foam is an indicator that it's almost done. Once the solids are caramel brown remove pan from heat and immediately pour butter into a large bowl, scraping in all the solids.
Whisk sugar, egg, and vanilla into brown butter. With a wooden spoon or rubber spatula, stir in oatmeal mixture. Mix until just combined. Stir in blueberries.
Drop dough by heaping tablespoons on prepared baking sheets, spacing them about 2 inches apart. Flatten the dough slightly with fingertips. Bake cookies until golden, 12 to 14 minutes, alternating sheets halfway through baking.
Transfer to cooling racks, and cool cookies on sheets until firm, 5 to 10 minutes. Transfer cookies directly to cooling racks and cool completely. Serve at room temperature or completely cooled.