Lemon Crisps

Ingredients

• 0.3 teaspoon double-acting baking powder 
• 0.3 teaspoon baking soda 
• 5 tablespoons butter softened
• 1 large eggs separated
• 1.5 cups flour all-purpose sifted
• 2 small optional: lemon 
• 0.1 teaspoon salt 
• 0.5 teaspoon vanilla extract pure

Equipment

• baking sheet
• baking paper
• oven
• whisk
• mixing bowl
• plastic wrap
• hand mixer

Directions

1. Whisk flour, baking powder, baking soda and salt in a bowl. Grate zest from 1 lemon directly over another mixing bowl. Squeeze 3 tablespoons lemon juice into a third bowl; set aside.
2. Add butter to lemon zest and beat with an electric mixer on medium until combined.
3. Add sugar a little at a time; beat 1 minute.
4. Add yolk (cover egg white with plastic wrap and refrigerate until ready to use) and half the flour mixture; beat on low until just combined.
5. Add lemon juice, vanilla and remaining flour mixture. Beat until just combined. Form dough into a log about 8 inches long and 2 inches in diameter. Cover tightly in plastic wrap. Refrigerate 3 hours.
6. Heat oven to 350°F. Line 2 baking sheets with parchment paper.
7. Cut dough into 40 thin rounds and place on baking sheets.
8. Whisk egg white with 1/4 teaspoon water; brush on top of cookies. Dust each with a bit of sugar.
9. Bake 8 to 10 minutes or until edges are golden. (If baking both sheets of cookies at the same time, alternate positions halfway through.)
10. Let cool on baking sheet 5 minutes.
11. Transfer to wire racks to cool completely.
12. Self