Line a 9x13 baking sheet with parchment paper, and make sure the paper runs over the sides a bit. You’ll use it to remove everything once chilled.
Into a food processor, pour ½ cup of sugar and 1½ tbsp. of dried lavender. Process for about 30 seconds until the flowers are fully chopped into the sugar. In a mixing bowl, pour the lavender sugar into 2½ cups of plain sugar and mix until fully incorporated.
Melt 8 oz. of butter. In a separate mixing bowl, combine melted butter with ½ cup of mixed lavender sugar, 2 tsp. vanilla extract and ½ tsp. salt in a medium-size bowl. Once combined, mix in 2 cups of flour until the dough is smooth but a little crumbly. Add scoop it onto your lined pan. Lay plastic wrap over the dough and press it to distribute evenly onto the bottom. You can also use your bare hands, but the dough is pretty sticky so it’s trickier without plastic wrap. Bake for 20-25 minutes at 350 F. until the crust is golden brown.
While your crust is baking, zest one lemon and juice 1 cup fresh lemon juice (from about 4-5 lemons). Whisk lemon zest with the rest of your lavender sugar,8 eggs, and lemon juice in a large bowl, then gently mix in ½ cup of flour. It will seem really liquidy for a custard base, but that’s OK. It’s supposed to be.
Once the crust is finished baking, keep the pan in the oven, pull it out just enough for you to evenly pour in your lemon mixture. If you remove the pan, and then pour, you may spill it everywhere (Like I did the first time). Lower the temperature to 325 F., and push the pan back into the oven. Bake for 30 minutes.
Let the pan cool at room temperature for about 30 minutes, then chill in the fridge for at least 3 hours. Remove by carefully lifting the parchment paper from the sides, and cut into bars. Sprinkle with confectioners sugar, then garnish with fresh or dry lavender if you’re extra fancy.
These lemon bars will last in an airtight container for a week, but I promise, they're too tasty to actually last that long.