Brown Butter Apple Blondies with Cinnamon Maple Glaze

1. Heat the oven to 350°F. Line a 9-by-13-inch baking dish with parchment paper. 2. Place 3/4 cup salted butter in a medium pot over medium heat. Cook, stirring frequently, until browned and nutty-smelling, about 2–3 minutes. Take off the heat and stir in the apple butter and 1 cup brown sugar. Let the mixture cool for 5 minutes. 3. Whisk in the eggs and vanilla. Stir in the flour, baking powder, 1 teaspoon cinnamon, nutmeg, and kosher salt just until combined. Spread the dough evenly in the prepared dish. 4. Toss the chopped apples with the remaining 1/2 cup brown sugar and 1 teaspoon cinnamon. Scatter evenly over the dough. 5. Bake for 25–30 minutes, until the center is just set. If liquid remains in the middle, gently swirl it around the pan and bake for another 5 minutes. Allow the blondies to cool. 6. For the glaze, heat 3 tablespoons salted butter in a small pot over medium heat until lightly browned and fragrant, about 2–3 minutes. Remove from the heat and whisk in the maple syrup, powdered sugar, 1/2 teaspoon cinnamon, and flaky sea salt. 7. Drizzle the glaze over the blondies and let it set for 5 minutes. Slice into 24 bars and serve.