Preheat oven to 350°F (175°C) and line an 8×8-inch pan with parchment paper
In a bowl, whisk melted butter, brown sugar, and granulated sugar until smooth
Add eggs one at a time, mixing well after each
Stir in vanilla extract
Fold in flour and salt just until combined
Spread blondie batter evenly into prepared pan
In a separate bowl, beat cream cheese until smooth
Mix in sugar, egg, and vanilla until creamy and lump-free
Spoon cheesecake mixture evenly over the blondie base
Smooth the top gently, avoiding pressing down
Bake for 35–40 minutes, until edges are set and center has a slight jiggle
Cool completely, then refrigerate before slicing