Here's an easy-to-prepare Finnish Rhubarb Tart recipe to highlight those blushing tart rhubarbs. It can be baked into round tarts or rectangular pans to make bars. This is a crustless tart with a frangipane cake filling that cools into a sturdy layer that you can eat with your hands. It pairs well with vanilla bean ice cream or whipped cream when eaten warm. This recipe was adapted from Endless Vacation magazine.