01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together flour, baking powder, and salt in a medium bowl. Set aside.
03 - Beat butter and sugar in a large bowl until light and fluffy, about 2-3 minutes.
04 - Mix in egg yolk, lemon zest, lemon juice, and vanilla extract until fully combined.
05 - Gradually add dry ingredients to wet mixture, mixing just until incorporated.
06 - Fold in chopped lavender until evenly distributed throughout dough.
07 - Scoop rounded tablespoons of dough, roll into balls, and place 2 inches apart on prepared baking sheets.
08 - Gently press thumb or back of teaspoon into center of each ball to create an indentation.
09 - Bake for 10 minutes. Remove from oven and reinforce indentations if needed.
10 - Fill each indentation with about 1/2 teaspoon of lemon curd.
11 - Return cookies to oven and bake for additional 2 minutes, until edges are very lightly golden.
12 - Cool on baking sheet for 5 minutes, then transfer to wire rack to cool completely.