Chocolate Tart Dough

• 10 tablespoons (141g) cold unsalted butter, cut into pieces
• 3/4 cup (150g) sugar
• Coarse salt
• 1 large egg
• 1 large egg white
• 2 1/2 cups (310g) all-purpose flour
• 1/2 cup (50g) unsweetened cocoa powder (preferably Valrhona)
• 1 teaspoon (4g) baking powder

1. Put the butter in the bowl of a standing mixer fitted with the paddle along with the sugar and a pinch of salt.
2. Beat until pale.
3. In a separate bowl, whisk the egg and egg white together.
4. Add gradually to the butter, scraping the bowl often and beating until smooth.
5. Whisk the flour, cocoa powder, and baking powder together.
6. Add to the wet ingredients and mix on low speed only until blended.
7. Dump the dough onto a lightly floured work surface and divide in half.
8. Shape each half into a small brick, wrap in plastic, and refrigerate for at least 1 hour before rolling.
9. The dough will keep for several days in the refrigerator and for 2 months in the freezer.
10. Defrost before rolling.
11. Add 1/2 teaspoon (0.5g) ground allspice and 1/8 teaspoon (0.2g) ground cinnamon to the bowl when you are beating the butter and sugar.

cold unsalted butter, sugar, salt, egg, egg white, flour, cocoa, baking powder

Taken from www.epicurious.com/recipes/food/views/chocolate-tart-dough-376831 (may not work)