Instructions

• Preheat oven to 350°F (177°C). Line two cookie sheets with parchment paper or silicone baking mats.
• In the bowl of an electric mixer fitted with the paddle attachment, cream 1/2 cup softened butter, 3/4 cup peanut butter, 3/4 cup packed brown sugar, and 1/4 cup granulated sugar until light and combined.
• Add 1 large egg, 1 teaspoon vanilla, 1 tablespoon milk, 1/4 teaspoon salt, and 1/2 teaspoon baking soda to the mixer. Mix until fully incorporated.
• With the mixer on low speed, gradually add 1 3/4 cups all-purpose flour and mix until the dough comes together and no dry flour remains.
• Using a tablespoon or a 1-Tbsp cookie scoop, portion the dough into 1-tablespoon-sized balls and place them about 2 inches apart on the prepared cookie sheets.
• Flatten each dough ball with the tines of a fork to create a crisscross pattern.
• Bake one sheet at a time (or both if your oven allows even baking) for 8–10 minutes, until the edges are set and the bottoms just begin to brown.
• Let the cookies cool on the baking sheet for 2–3 minutes, then transfer them to a wire rack to cool completely.
• Make the filling: in a medium bowl, beat 4 tablespoons softened unsalted butter and 1/2 cup creamy peanut butter until smooth.
• Gradually add 2 cups powdered sugar and beat until incorporated and the mixture is thick. Add 2 teaspoons vanilla extract and 1 teaspoon maple extract and beat to combine.
• Add 3 tablespoons heavy whipping cream to the filling and beat. If the filling is too stiff, add additional heavy cream 1 tablespoon at a time (up to a total of 5 tablespoons) until you reach a spreadable consistency.
• Turn half of the cooled cookies upside down, spread an even layer of filling on each, and top with the remaining cookies to form sandwiches.
• Store the sandwich cookies in an airtight container at room temperature for up to 3 days.