Makes one 9-inch tart
Marian Parker, who lives in Brookline and Lenox, sent us this savory tart. “I got this recipe when I lived in Seattle in the early 1980s. It was intended for Walla Walla sweet onions, which we only get here (in Boston) every once in a while. It does just as well with Vidalia onions.’’ Parker writes that the tart has been served at many Tanglewood picnics. The secret to the sweet onion flavor is taking the time to caramelize the onions — about 1 hour — but it’s worth the effort.
One 9-inch single crust pastry shell3tablespoons butter3large sweet onions, such as Vidalia, Walla Walla, or OSO Sweet, thinly sliced 3eggs⅔cup yogurt⅓cup half-and-half Salt, to taste⅛teaspoon freshly ground pepper⅛teaspoon nutmeg¼cup grated Parmesan
1. Set the oven at 375 degrees. Have on hand a rimmed baking sheet.
2. Line the unbaked shell with foil and add weights or dried beans. Bake for 15 minutes. Remove the foil and weights and bake 8 minutes more or until the pastry is cooked on the bottom. Save the beans (reuse for baking).
3. In a large heavy skillet over medium heat, melt the butter. Add the onions and cook, stirring often, for 1 hour or until the onions are very tender and turn a golden caramel color. If necessary, turn up the heat to evaporate any liquid in the pan. Cool the onions slightly and spread in baked shell.
4. In a bowl, whisk together eggs, yogurt, half-and-half, salt, pepper, and nutmeg.
5. Set the pie on the baking sheet. Pour the custard over the onions. The mixture will come right to the top. With a fork, gently separate the onions so the custard falls to the bottom of the pastry. Sprinkle with Parmesan.
6. Transfer the pie on the sheet to the oven. Bake for 35 minutes or until a knife inserted in center comes out clean. Remove the tart from the oven and let it settle for 15 minutes. Adapted from Marian Parker