Gluten-Free Triple-Threat Chocolate Squares

Ingredients

• 8 ounces mascarpone cheese, softened
• 4 ounces bittersweet chocolate, melted
• 1 yolk from large egg, room temperature
• 2 tablespoons espresso, room temperature
• ½ teaspoon pure vanilla extract
• pinch of kosher salt
• 187 grams all-purpose gluten-free flour mix
• 1.5 ounces unsweetened cocoa powder (sift if lumpy)
• ¼ teaspoon kosher salt
• 16 tablespoons unsalted butter, softened
• 12 ounces granulated sugar
• 3 large eggs, room temperature
• 1-1/2 teaspoons pure vanilla extract
• 5 ounces semisweet chocolate chips
• 4 tablespoons unsalted butter, room temperature
• maldon salt for finishing