1. Craft the Pistachio Crunch Filling: In a small bowl, gently stir together the pistachio cream and toasted kataifi until it's well combined. Scoop this mixture into 1-tablespoon portions and place them onto a small baking sheet lined with wax paper. Pop this sheet into the freezer to chill and firm up while you get the cookie dough ready.
2. Prepare the Easy Chocolate Cookie Dough: Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. In a large microwave-safe bowl, melt the butter. Stir in the cocoa powder and avocado oil until smooth. Let this mixture cool completely so it's not warm to the touch. Once cooled, add the granulated sugar, light brown sugar, large egg, and vanilla extract, mixing well. In a separate medium bowl, whisk together the cake flour, baking soda, baking powder, and salt. Gradually add the dry ingredients to the wet mixture, stirring just until everything is combined and a soft dough forms.
3. Assemble Your Stuffed Cookies: Retrieve your firm pistachio filling balls from the freezer. Scoop the cookie dough into 2 ½-tablespoon portions. Roll each dough portion into a smooth ball, then use your thumb to create a small indentation in the center. Place one frozen pistachio filling ball into the indent and carefully wrap the cookie dough around it, sealing the filling completely. Roll it gently between your palms to ensure a smooth, round cookie.
4. Bake and Decorate: Place the stuffed cookie dough balls on your prepared baking sheet, leaving at least 2 inches between them. Bake for 10 minutes. Once out of the oven, use the clean bottom of a measuring cup or glass to gently flatten each warm cookie. This helps create that perfect bakery-style texture! Let the cookies cool completely on the baking sheet—they'll be delicate when warm. Once cooled, drizzle them with melted chocolate and sprinkle generously with crushed pistachios for a beautiful finish. Allow the chocolate to set before enjoying these delightful summer treats!