Free-Form Apple Onion Tart

Pastry:
1½ cups flour
1 tsp. sugar
½ tsp. salt
8 T. butter
1 T. white vinegar
4-5 T. ice water

Onions:
1 lg. red onion, peeled, root intact
2 lg. spanish onions, peeled with root intact
2 T. olive oil
2 T. dijon mustard
3 T. thyme
salt/pepper
3 T. balsamic vinegar

Apple Filling:
4 golden delicious apples
2 T. butter
2 T. sugar
pinch of nutmeg

Pastry: In the bowl of a food processor, combine the flour, sugar, and salt, and pulse to sift together. Add the butter, pulsing to mix until the mixture resembles sand. Mix together the vinegar and 4 T. water. Mix vinegar mixture into the flour, enough that the dough comes together. Turn dough out onto a lightly floured board, and knead until smooth. Shape into a flat, round, cake. Wrap in foil and refrigerate 20 minutes.

Onions: Preheat the oven to 400° F. Cut each onion into 6-8 wedges, keeping some root on each piece to hold together. Mix olive oil, mustard, thyme, salt and pepper in a bowl. Add the onions, and toss gently to coat. Arrange onions in a baking dish, rounded sides down. Sprinkle with vinegar. Cover with foil, roast for 45 minutes. Remove foil, roast for 30 minutes more, until very tender.

Apples: Peel, core, and quarter apples. Cut each quarter into 3 pieces. In a large skillet, melt butter, add apples, and sprinkle with sugar and nutmeg. Cook over medium heat for about 10 minutes.

Set oven at 400° F. Roll out dough on a floured surface to about 9x11 inches. Transfer to floured baking sheet. Place apples on dough, and onions on top of apples. Curl up edge of dough around filling. Bake for approximately 35 minutes, or until pastry browns.

From the Boston Globe, probably 15 years ago but I don't have the original recipe--Jay sent me a copy.