
¼ cup fresh lemon juice
1 cup unsalted butter, softened; divided
2 cups all-purpose flour
1 teaspoon baking powder
½ teaspoon salt
1½ cups granulated sugar, divided
3½ teaspoons lemon zest, divided
1 large egg, room temperature
2 teaspoon pure vanilla extract
1 tablespoon poppy seeds, plus additional for garnish
1 recipe Royal Icing
1 recipe Candied Lemon Peel