Preheat your oven to 350°F (175°C) and prepare a 9x9-inch baking pan by greasing it lightly.

In a mixing bowl, combine all-purpose flour, powdered sugar, and a pinch of salt. Add in cold unsalted butter and mix until it resembles coarse crumbs.

Press the crust mixture firmly into the baking pan and bake for 15-20 minutes or until golden brown.

Combine sugar, culinary lavender, and water in a small saucepan. Heat gently until the sugar dissolves. Strain to remove lavender buds.

In a separate bowl, whisk eggs and cooled lavender syrup together. Add freshly squeezed lemon juice and zest, mixing well.

Sift in remaining flour and powdered sugar, whisking until smooth.

Pour the filling over the pre-baked crust and bake for another 20-25 minutes until set but jiggles slightly in the center.

Let the bars cool to room temperature, then refrigerate for at least 2 hours before serving.

Cut into squares and garnish with lemon slices and sprigs of lavender before serving.