When water is added to wheat flour, the proteins inside the flour connect to form networks of gluten. Thats great for dense baked goods like bagels, but you want to limit that interaction in a flaky dessert.
For starters, pick the right flour — one without too much protein. Pastry flour will make your crust crumble, but cake flour will be way too dense. Go with all-purpose flour.
Then, pick the right booze.