1. Brown the butter by melting it in a saucepan over medium heat for 5 to 7 minutes until golden and nutty, then remove from heat and let cool slightly.

2. Preheat the oven to 350°F and line an 8×8-inch baking dish with parchment paper.

3. Whisk together the brown sugar, cooled brown butter, pumpkin butter, egg, and vanilla extract in a large bowl.

4. In a separate bowl, combine the flour, pumpkin seasoning, baking powder, and salt; gradually fold into the wet mixture until just combined.

5. Pour the batter into the prepared pan and bake for 25 to 30 minutes until the edges are set and a toothpick inserted in the center comes out with moist crumbs.

6. Allow the blondies to cool completely in the pan on a cooling rack before frosting.

7. Beat the softened cream cheese and butter until smooth, then gradually add powdered sugar and vanilla extract, mixing until creamy to make the cream frosting.

8. Spread the frosting over the cooled blondies, sprinkle with pumpkin seasoning if desired, then slice into squares and serve.