Preheat the oven to 350°F (175°C).
In a medium bowl, whisk together the all-purpose flour, baking soda, and salt. Set aside.
In a large bowl, using an electric mixer, beat the softened unsalted butter, creamy peanut butter, granulated sugar, and light brown sugar together until creamy and smooth, about 2-3 minutes.
Add the egg and pure vanilla extract to the peanut butter mixture and beat until fully incorporated.
Gradually add the dry flour mixture to the wet ingredients, mixing on low speed until just combined.
Press the cookie dough evenly into the bottom and slightly up the sides of a 9-inch (23 cm) round tart pan or pie dish to form a crust.
Bake the crust in the preheated oven for 10-12 minutes, or until the edges are lightly golden and the center is set.
Remove the crust from the oven and allow it to cool completely before adding any filling or toppings.