– 2 ¾ cups (399 g) low FODMAP gluten-free all-purpose flour, such as Bob’s Red Mill 1 to 1 Baking Flour, plus extra for pan – 2 teaspoons salt – 1 teaspoon baking powder; use gluten-free if following a gluten-free diet – 1/2 pound (226 g; 2 sticks) unsalted butter, at room temperature, cut into pieces – 1 cup (198 g) sugar – ½ cup (107 g) firmly packed light brown sugar – 1 ¼ teaspoons pure vanilla extract – 3 large eggs, at room temperature – 2 cups (512 g) smooth no-stir style peanut butter (Skippy brand no-stir style recommended) – 1 1/2 cups (480 g) strawberry or raspberry jam, sweetened with sugar, not high fructose syrup; I like Smucker's Natural – 1/2 cup (73 g) salted peanuts, coarsely chopped; optional