Ingredients
4 tablespoons softened unsalted butter
1/2 cup packed light-brown sugar
1/4 cup creamy peanut butter
1/4 teaspoon baking soda
1/4 teaspoon kosher salt (we use Diamond Crystal)
1 large egg yolk, room-temperature
1/4 teaspoon pure vanilla extract
3/4 cup unbleached all-purpose flour
1/4 cup quick-cooking oats
1 recipe Frozen-Berry Jam
Preparation
Preheat oven to 375°F. Combine butter, brown sugar, peanut butter, baking soda, and salt in a large bowl and beat with an electric mixer on medium-high speed until light and creamy, about 2 minutes.
Beat in egg yolk and vanilla, then add flour and mix until just combined. Scoop dough into 1-inch balls and roll in oats to coat; place cookies on parchment-lined baking sheets, spaced 1 inch apart.
Bake, rotating pans halfway through, until puffed and just set around edges, 10 to 12 minutes. While cookies are still warm, indent centers with the end of a wooden spoon; fill each with 1/2 teaspoon jam. Transfer to a wire rack and let cool completely before serving.
