Preheat oven to 400° F, with a pizza stone on middle rack (or, if you don’t have one, place a baking sheet in the oven to preheat while you assemble tart).
On a piece of parchment, roll out pastry to a large rectangle, big enough to fit onto your stone or baking sheet. Prick surface of dough with tines of a fork, leaving a solid 1-inch border at edge. Toss greens and oil in a bowl with oil, salt and pepper; arrange greens over pricked area of tart. Scatter feta slices and chilies over greens.
Slide parchment onto baking stone (or preheated baking sheet). Bake tart until puffed and golden at edges, about 15 minutes. Drizzle tart with lemon juice before slicing and serving.
Before her diagnosis, Caroline wrote a book on cakes called Cake Magic!. She started developing a birthday cake using her gluten-free mix found in that book. Check out other recipes she’s developing for her new life—and the stories behind them—on her blog, The Wright Recipes. Her next book, Soup Club, is a collection of recipes she made for her underground soup club of vegan and grain-free soups she delivers every week to friends throughout Seattle's rainy winter. (Available February 2021.)