For those who can't find lavender syrup, it's easy to make your own: just bring 1 cup sugar, 1/2 cup water, and a bunch of fresh or dried lavender to a boil, stir to dissolve the sugar, turn off the heat and let steep for about 20 minutes.

Then fine strain to remove the lavender. The result is roughly the color of elderflower liqueur, but you can add a drop of red and one of blue food coloring to make it lavender-colored (though in this recipe the creme de violette takes care of that).