Begin by placing the butter in a medium saucepan over medium heat. Stir gently as it melts and watch closely as it foams.

After about 6 to 8 minutes, the butter should turn golden with little brown bits forming at the bottom. Remove it from heat and pour into a heat-safe bowl to cool for 5 to 10 minutes.

In a mixing bowl, blend together the brown butter and brown sugar until smooth.

Add the egg, egg yolk, and vanilla extract, mixing until fully combined.

Gradually stir in the pistachio cream, ensuring evenly distributed flavor.

Gently fold in the flour and salt until no dry streaks remain. Don't overmix, a few lumps are okay.

Fold in the chocolate chips and chopped pistachios.

Preheat your oven to 350°F (175°C) and line or lightly grease an 8x8-inch baking pan.

Spread the batter evenly into the prepared pan and swirl additional dollops of pistachio cream on top.

Bake for 20 to 25 minutes, until edges are lightly golden and the center is soft to the touch.

Allow the blondies to cool completely in the pan before slicing.