Preheat your oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper.

Melt ½ cup of unsalted butter over low heat and set aside to cool slightly.

In a mixing bowl, combine melted butter with 1 cup of light brown sugar and stir until smooth.

Incorporate 2 large eggs and 1 teaspoon of vanilla extract, mixing until blended.

Sift together 1 cup of all-purpose flour and a pinch of salt, then fold into the wet mixture.

Beat together 8 ounces of cream cheese and ¼ cup of granulated sugar until smooth, then mix in 1 egg yolk and a splash of vanilla.

Spread the blondie batter into the prepared pan, dollop with the cheesecake mixture, and swirl gently.

Spoon dollops of 2 tablespoons of pistachio paste over the cheesecake and swirl gently again.

Bake for 30–35 minutes until golden around the edges and a slight jiggle remains in the center.

Cool completely in the pan, then refrigerate for at least one hour before slicing into squares.