Brown the butter: Melt butter in a medium saucepan over medium heat. Swirl occasionally for 5-7 minutes as it foams and pops, until golden amber with fragrant toasty browned milk solids. Pour into a heatproof bowl and let cool 10 minutes.

Blot pumpkin & prep pan: Preheat oven to 350°F (177°C). Line an 8x8 or 9x9 inch metal square baking pan with parchment paper, leaving an overhang for easy lifting. Spread pumpkin puree onto 3 layers of paper towels and gently press with another layer to blot out excess moisture (crucial for dense, chewy blondies rather than cakey bars!).

Mix wet & dry: In a large bowl, whisk cooled brown butter, brown sugar, and granulated sugar for 1 full minute until glossy. Whisk in blotted pumpkin puree, whole egg, egg yolk, and vanilla until velvety. In a separate bowl, whisk flour, cinnamon, nutmeg, ginger, baking powder, and salt. Fold dry ingredients into wet with a spatula until just combined. Fold in white chocolate chips if using.

Make cream cheese swirl: In a small bowl, beat softened cream cheese, sugar, egg yolk, and vanilla with a fork or hand mixer until completely smooth and lump-free.

Spread & marble: Spread the thick pumpkin batter evenly into the prepared pan. Dollop spoonfuls of cream cheese mixture across the surface. Use a wooden skewer or butter knife tip to drag through the dollops in figure-eight loops to create a gorgeous marbled swirl pattern.

Bake to fudgy perfection: Bake at 350°F for 28-32 minutes until edges are golden brown and center is gently set with a slight fudgy jiggle (a toothpick inserted in the blondie portion should come out with a few moist crumbs, not wet batter). Cool completely in the pan on a wire rack before slicing into clean, sharp squares. Enjoy with a hot autumn latte!