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