Cooking spray or butter, for coating the pan
2 cups all-purpose flour
1/2 teaspoon baking powder
1/2 teaspoon fine salt
12 tablespoons (1 1/2 sticks) unsalted butter, at room temperature
1 1/3 cups granulated sugar
1 1/3 cups natural creamy peanut butter (no sugar added), at room temperature
1 large egg
1 teaspoon vanilla extract
1 1/2 cups Concord grape jelly, at room temperature
2/3 cup coarsely chopped salted, roasted peanuts (optional)