Active time: 30 minutes
Total time: 45 minutes
Yields 4 dozen cookies
Finely-grated zest and juice from 6 Meyer lemons
16 ounces (4 sticks) unsalted butter
4 cups all-purpose flour
2 teaspoons baking powder
1 teaspoon salt
3 cups sugar
2 large eggs
4 teaspoons pure vanilla extract
2 tablespoon poppy seeds, plus more for sprinkling
1. Preheat the oven to 375 degrees. Line 4 baking sheets with parchment paper. Bring lemon juice to a simmer in a small saucepan over medium heat; cook until reduced by half. Add 2 sticks of butter; stir until melted.
2. Whisk together the flour, baking powder, and salt in a large bowl.
3. Cream remaining 2 sticks of butter with 2 cups of sugar on medium speed in the bowl of an electric mixer fitted with the paddle attachment. Mix in eggs and lemon butter. Mix until pale, about 3 minutes. Mix in vanilla and half of the lemon zest. Mix in flour mixture and poppy seeds.
4. Stir together remaining 1 cup sugar and the other half of the lemon zest. Roll spoonfuls of dough into 1 1/2-inch balls; roll them in sugar mixture. Place the dough balls 2 inches apart on baking sheets. Press each gently with the flat end of a glass dipped in sugar mixture until 1/4 inch thick. Sprinkle with poppy seeds.
5. Bake until just browned around bottom edges, 10 to 11 minutes. Transfer to wire racks; let cool completely.