In a mixing bowl, whisk together 1 ¾ cups of all-purpose flour, ½ cup of unsweetened cocoa powder, ¼ cup of granulated sugar, and ½ teaspoon of kosher salt until well combined. Cut in ½ cup of cold unsalted butter until the mixture resembles coarse crumbs.

Form the dough into a ball, wrap in plastic wrap, and refrigerate for at least 30 minutes.

Preheat your oven to 350°F (175°C). Place the rolled-out dough into tart pans, pressing it gently into the sides and bottoms. Prick the bottoms with a fork to prevent air bubbles. Bake for 10-12 minutes.

In a large bowl, beat together 8 ounces of cold cream cheese and 1 cup of smooth peanut butter until smooth. Gradually add 1 ½ cups of confectioners' sugar and mix until fully combined. Fold in ½ cup of mini chocolate chips.

Spoon the peanut butter filling into each cooled tart shell, leveling the surface with a spatula. Cover and refrigerate for about 2 hours.

Once set, top each tart with white frosting and sprinkle with white sanding sugar.