Preheat your oven to 350°F (175°C). Combine ½ cup of granulated sugar with 2 teaspoons of dry culinary lavender in a food processor and pulse until finely chopped.

In a medium bowl, mix the lavender-infused sugar with 1 cup of white granulated sugar until evenly blended.

Combine melted salted butter, ¼ cup of lavender sugar, and real vanilla extract in a bowl, whisk until mixed, then incorporate flour to form a smooth dough. Refrigerate for 10-15 minutes.

Press the dough evenly into the tart tin, cover with foil or wax paper, and add pie weights. This prevents puffing during baking.

Bake for 25-30 minutes, or until the crust is lightly golden. Remove and let it cool slightly.

Whisk together lemon zest, lemon juice, and eggs in a large mixing bowl. Gradually mix in the remaining lavender sugar and fold in ¼ cup of flour.

Pour the custard mixture into the cooled baked crust. Reduce oven temperature to 325°F (160°C) and bake for an additional 30 minutes.

Cool at room temperature for 10-20 minutes, then refrigerate for at least 4 hours to firm up the custard.