Directions

1. Adjust oven racks to upper-middle and lower-middle positions and heat oven to 375 degrees. Line 2 baking sheets with parchment paper. Whisk flour, baking powder, baking soda, and salt in large bowl.
   
2. With electric mixer on medium speed, beat butter and sugar until fluffy. Add eggs, one at a time, and beat until incorporated. Reduce speed to low and beat in sour cream and lemon zest. Add flour mixture and mix until combined.
   
3. Refrigerate dough until slightly firm, about 1 hour. Drop rounded tablespoons of batter onto prepared baking sheets, spacing cookies 2 inches apart. Bake until just golden around edges, about 15 minutes, switching and rotating sheets halfway through baking. Cool on baking sheets. Repeat with remaining dough. (Cookies can be stored in airtight container for 3 days.)