Tomato and Caramelized Onion Tart

Now that you have learned how to make the Butter Pastry Dough you are ready to fill it and bake it!  I make this frequently in the summer when tomatoes are at their best.  But, really, anytime of the year is a good time to make this tart.  Whether you have wonderful summer tomatoes or not, they will roast in the oven and taste delicious!  I always serve this at parties.  It can be baked the day before and left at room temperature until time to serve. 

Tomato and Caramelized Onion Tart
adapted from Gourmet May 1995

2 large onions (about 1 1/2 pounds), sliced thin
2 tablespoons olive oil
butter pastry dough
1/2 pound Jack cheese, shredded (about 2 cups)
1 pound plum or other tomatoes cut into 1/2-inch wedges
(or 1/2 pound each of medium red and yellow tomatoes, cut into 1/2-inch wedges)
kosher salt
freshly ground pepper

In a large heavy skillet cook onions with salt to taste in oil, covered, over moderate heat, stirring occasionally, until softened, about 20 minutes. Remove lid and cook onions, stirring occasionally, until golden and any liquid evaporates. Remove skillet from heat to cool onions slightly. (I usually make these several days in advance and store in the refrigerator until time to assemble tart.)

Preheat oven to 375°F. Roll out butter pastry dough and put in tart pan (see directions in butter pastry dough post)--make sure to put aluminum foil around tart pan to catch drips.  Spread onion mixture over dough and top with cheese. Arrange tomato wedges in concentric circles over cheese and season with salt and pepper.

Bake tart in middle of oven 1 hour, or until pastry is golden, and cool on a rack. Remove rim of pan if necessary. Serve tart warm or at room temperature.