Nutty White Chocolate Blondies

12 tablespoons unsalted butter (1 1/2 sticks), melted

1 1/3 cups packed light brown sugar

4 teaspoons vanilla extract

2 teaspoons kosher salt

1 teaspoon baking powder

2 large eggs, at room temperature, lightly beaten

1 1/4 cups all-purpose flour

1 cup nuts, such as pecans or walnuts, toasted and coarsely chopped

1 cup white chocolate chips

Heat the oven to 350°F and arrange a rack in the middle. Coat a 13-by-9-inch baking dish with butter and flour; set aside.

Combine butter and brown sugar in a large bowl and stir until evenly incorporated. Add vanilla, salt, and baking powder, and stir until thoroughly combined.

Add eggs, and stir briefly until evenly incorporated. Add flour, and stir until just incorporated (no white streaks should remain). Stir in nuts and chips until just combined.

Transfer batter to the prepared baking dish, and bake until golden brown and set, about 25 minutes. Remove from the oven and place on a wire rack to cool completely before cutting.