Blueberry lovers, this is the pie for you. Piled into a vanilla wafer crust is a mound of fresh berries held together with a thickened blueberry puree flavored with elderflower liqueur. It's the ultimate expression of fresh blueberry goodness. Greek yogurt combines with beaten whipping cream for a luscious topping with a little tang to complement the berries. You can substitute orange liqueur for the elderflower, or stir in fruit juice (such as blueberry, grape or apple) for an alcohol-free version. The pie is best enjoyed the day it's made because the crust will be at its crispy best.