01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - In a medium bowl, whisk together the all-purpose flour, baking powder, and salt until well blended. Set aside.
03 - In a large bowl, beat the unsalted butter and granulated sugar together using an electric mixer until light and fluffy, approximately 2-3 minutes.
04 - Mix in the egg yolk, lemon zest, lemon juice, and vanilla extract until fully incorporated into the butter mixture.
05 - Gradually add the flour mixture to the wet ingredients, mixing on low speed just until the flour is fully absorbed and a dough forms.
06 - Fold in the finely chopped dried culinary lavender by hand until evenly distributed throughout the dough.
07 - Scoop rounded tablespoons of dough and roll between your palms to form smooth balls. Arrange them 2 inches apart on the prepared baking sheets.
08 - Gently press your thumb or the back of a teaspoon into the center of each dough ball to create a deep well for the filling.
09 - Bake the cookies for 10 minutes, or until just set. Remove from the oven and press the indentations again if they have puffed up during baking.
10 - Fill each indentation with approximately 1/2 teaspoon of lemon curd, being careful not to overflow the wells.
11 - Return the cookies to the oven and bake for an additional 2 minutes, or until the edges are very lightly golden and the filling is set.
12 - Let the cookies rest on the baking sheets for 5 minutes to firm up, then transfer to a wire cooling rack to cool completely before serving.