01 - Preheat oven to 350°F. Line a 9x9-inch baking pan with parchment paper, leaving overhang for easy removal.
02 - Cream butter and sugar until light and fluffy. Add flour and salt; mix until just combined. Press dough evenly into pan bottom.
03 - Bake crust for 18-20 minutes until lightly golden. Remove from oven and let cool slightly.
04 - Whisk eggs and sugar until pale and smooth. Add lemon zest, lemon juice, crushed lavender, flour, heavy cream, and salt. Whisk until fully combined.
05 - Pour filling over slightly cooled crust. Return to oven and bake for 18-20 minutes until center is just set.
06 - Let cool completely in pan. Refrigerate for at least 1 hour before slicing.
07 - Dust with powdered sugar before serving. Cut into 16 bars.