1-First, freeze the pistachio cream spread by placing it on parchment paper and freezing for at least 1 hour until solid. This step ensures a gooey center that surprises with every bite. Next, line a cutting board with parchment paper to chill the dough later, keeping things organized as you go.

2-Now, mix the dry ingredients: combine 180 grams all-purpose flour, 1 tablespoon cornstarch, ½ teaspoon baking powder, ½ teaspoon baking soda, and ½ teaspoon salt in a small bowl. In a large bowl, whisk the 115 grams melted and cooled unsalted butter with 100 grams brown sugar and 50 grams granulated sugar until smooth. Add 1 large room-temperature egg and 1 teaspoon vanilla extract, whisking until fully blended.

3-Mixing and Chilling the Dough: Add the dry mixture to the wet ingredients and stir until just combined, leaving a few patches of flour for the best texture. Fold in 100 grams roughly chopped semi-sweet or dark chocolate and 50 grams roughly chopped unsalted pistachios to add crunch and flavor. Use a 4-tablespoon scoop to portion the dough onto the lined board, then refrigerate for about 1 hour until firm.

4-Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Flatten each dough ball, place a frozen pistachio cream piece in the center, and seal it inside. Arrange the stuffed balls on the baking sheet with space between them, and press on extra chocolate, pistachios, or cream pieces as you like.

5-Baking and Finishing Touches: Bake for 11-12 minutes until the edges set but the centers stay soft. Right after baking, sprinkle flaky salt on top for a tasty finish. Let the cookies cool on the sheet for 5 minutes before serving warm or letting them firm up as they cool.