This article is adapted from the March 12, 2022, edition of Gastro Obscura’s Favorite Things newsletter. You can sign up here. This week, I summoned the spirit of spring by making Shaker lemon pie, one of the sunniest sweets I know. It doesn’t sound like much: a simple combination of sugar, lemons, egg, and pastry crust. But this sweet-and-sour treat is an absolute delight, and I’m bummed that more people don’t know about it. So I’ve become something of a Shaker pie hype-woman. Its obscurity isn’t due to a lack…