Onion Caraway Shortbread - Boys of Cooking

Ingredients

• 13 Tbl (about 1 ¾ sticks) unsalted butter
• 1 cup finely chopped onion (1 medium)
• 1 ¼ cups all-purpose flour
• 1 Tbl powdered sugar
• ½ tsp baking powder
• 1 tsp caraway seeds
• 1 large egg white, slightly beaten
• 12 Tbl (1 ½ sticks) unsalted butter, softened
• ¼ tsp salt