Preheat your oven to 350°F (175°C) to prepare for baking the crust. Gather your ingredients and utensils.

In a large mixing bowl, combine the all-purpose flour, powdered sugar, and salt. Cut in the cold unsalted butter until it resembles coarse crumbs, then press it into a greased 9x9-inch baking pan.

Bake for 15-20 minutes until the crust is light golden brown and slightly firm to the touch. Allow it to cool slightly.

Prepare the lavender syrup by combining sugar, culinary lavender, and water in a small saucepan. Heat over medium until sugar dissolves, then steep for 20 minutes before straining.

In another mixing bowl, whisk together the eggs and prepared lavender syrup until smooth.

Add the lemon juice and zest into the egg-syrup mixture. Incorporate additional flour and powdered sugar until smooth, taking care not to over-mix.

Pour the filling over the pre-baked crust and spread evenly. Bake for an additional 20-25 minutes until set with a slight jiggle in the center.

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

Slice into squares and garnish with fresh lavender sprigs and thinly sliced lemon.