Makes 1 tart, about 6 servings
If you have a disk of pie dough and some vegetables, you can quickly and easily make a rustic savory tart for supper. This tomato-basil version is a delicious ode to summer, but the onion base in this recipe is a terrific jumping off point for all kinds of flavors. We recommend making a batch of onion base in advance and freezing it in small portions to use on a whim.
1 package Grand Central all-butter pie dough, thawed in refrigerator
2 tablespoons olive oil
2 tablespoons unsalted butter
2-3 onions (about 1 pound), thinly sliced
2 teaspoons kosher salt
1/2 to 3/4 cup shredded fontina, gruyere, feta or parmesan cheese (or use a mixture)
3-4 medium tomatoes, sliced
Egg wash: 1 egg whisked with 1 tablespoon water
Pre-heat oven to 350°F.
Heat olive oil and butter in large heavy saute pan over medium high. Add onions, sprinkle with salt and saute until onions release some liquid and begin to develop a few dark spots, about 10 minutes. Reduce heat to medium-low and continue cooking until onions are soft and toasty brown, about 20 minutes. Let cool, and add more salt if necessary. (You can make the onion base ahead of time and freeze or refrigerate until ready to use.)
Form the tart.
Line a baking sheet with parchment paper. On lightly floured surface, lightly roll out one pie dough circle until 14-16 inches in diameter. Transfer to parchment-lined baking sheet. Tightly wrap and reserve remaining pie dough for another use.
Spread 1 to 1 1/2 cups onion base over pastry, leaving a 3-inch border. Sprinkle with half the shredded cheese and arrange tomatoes in a single layer on top. Top with remaining shredded cheese. Carefully lift and fold border up and over the filling, letting the dough pleat about 8 to 10 times.
Brush dough with egg wash and bake tart for 40-45 minutes, rotating pan halfway through baking, until filling is bubbly and crust is deep golden brown. Let cool for 10 minutes. Top with fresh basil and serve warm or at room temperature.
Adapted from The Grand Central Baking Book