Coat a 9×9 pan with cooking spray. Line with parchment paper and spray again to make removal easy. Set aside.

In a large saucepan, melt butter over medium heat, then add marshmallows and stir until completely smooth.

Remove from heat, stir in vanilla and 1/3 cup pistachio butter until smooth and well incorporated.

Fold the cereal into your marshmallow mixture and mix until well coated. Work quickly as the mixture cools fast and becomes more difficult to handle.

Pour the cereal mixture into your prepared pan and press down firmly to level the top.

Melt chocolate chips in 30-second intervals in the microwave, stirring between each interval until smooth. For easier cutting later, stir in 1 tsp of coconut oil (optional).

Pour melted chocolate over the top of Rice Krispies. Warm the additional 1 tbsp of pistachio butter in the microwave for 20 seconds, then drizzle over the chocolate.

Use a toothpick to create beautiful swirls in the chocolate and pistachio butter.

Top with chopped pistachios and a generous sprinkle of flaked sea salt.

Let cool completely (about 2 hours) before slicing into 12 squares. Enjoy!