Add 3 sticks (339g) unsalted butter to a light-colored saucepan. Melt over medium heat, stirring often, until golden brown with nutty aroma and brown specks (5–8 minutes).

Preheat oven to 350°F (177°C) and line with parchment paper or lightly grease a 9x13 inch pan.

In a large bowl, beat the browned butter that's reserved for the crust with sugar until combined. Add egg and vanilla.

In a medium bowl mix flour, baking powder, and salt. Fold dry ingredients into the wet and mix until a thick dough forms. Press evenly into a greased or parchment-lined 9x13-inch pan.

In another large bowl, beat softened cream cheese and pumpkin purée until smooth and creamy. Beat in eggs, vanilla, and the rest of the browned butter. Stir in cinnamon, nutmeg, cloves, and salt.

Gradually mix in powdered sugar, 1 cup at a time, until filling is smooth and pourable.

Pour pumpkin filling over crust, spreading evenly. Bake at 350°F (177°C) for 40–50 minutes, until edges are set but center still jiggles slightly.

Let cool at room temperature for at least 1 hour (filling will firm up). Slice into squares. Optional: dust with powdered sugar or drizzle with brown butter maple glaze before serving.