THIS SAVORY pie must have been invented in or around Nice, as the filling is nicoise, a modified form of that marvelous mixture of vegetables lightly simmered in olive oil called ratatouille. While ratatouille can be eaten hot as an accompaniment to a main meat dish or cold as a salad, here it is the savory filling for a double-crust hors d'oeuvre pie, called a Bohemian tourte. (It serves exactly the same function as a quiche, but that word properly belongs to the province of Lorraine. In any other part of France, an open pie is called a tarte. If it has a top crust, it is a tourte.)

As to the origin of the name Bohemian, the general theory is that the idea of informality at table, as expressed by the serving of cold vegetables in a pie, was dramatized by the huge success of the opera "La Boheme" and the comic opera "The Bohemian Girl." Many informal dishes of that time were named Bohemian. Unconventional, almost picnic-style meal planning became the fashion all over France. So the Bohemian tourte spread from Nice across Provence and then northward into the region of the Drome.

There, 100 years later, Lydie Marshall, French-born New York cooking teacher, found a modified version of the old recipe. She has simplified the preparation by working out a basic food processor method for the French-style pate brisee, the light and buttery pastry for the thin crust. To get it right, you must stop the motor before the dough has time to ride up to a ball. That would toughen this particular kind of super-light French pastry. LYDIE MARSHALL'S BOHEMIAN TOURTE (6 to 8 servings) The pastry: 1 1/2 cups all-purpose flour 1/4 teaspoon salt 12 tablespoons butter (must be cold) 4 to 5 tablespoons ice water The ratatouille filling: 1 medium eggplant 2/3 cup olive oil, approximately 2 medium yellow onions, thinly sliced 3 pounds fresh or 2 28-ounce cans plum tomatoes, peeled, quartered, seeded, drained 4 cloves garlic, minced 2 teaspoons sugar 1 whole bay leaf 1 teaspoon dried thyme Coarse-crystal sea salt or kosher salt Freshly ground pepper Cayenne pepper 3 large egg yolks 1/2 cup pitted black olives, quartered 1/3 cup gruyere, freshly grated 1/3 cup parmesan, freshly grated 2 teaspoons cream

Peel and slice eggplant, salt and let stand 30 minutes.

Food processor method for pate brisee: Spread flour on bottom of food processor work bowl with steel blade in position; sprinkle in salt. Process 1 second. Dot flower evenly with 1/2-tablespoon pieces of butter. Turn motor on and off 10 times, in half-second bursts. Sprinkle in all of ice water. Snap motor on and off in half-second bursts (usually about 4 to 7) until it achieves the texture of tiny niblet corn. Add more ice water, if necessary. Do not run motor so long that dough rides up onto blades as a ball.

Turn dough onto lightly floured pastry board. Gradually working your way around the pile, knead about 2 tablespoons at a time firmly with heel of hand, pushing it away from you, to bind butter and flour together. Gather it into ball. If still crumbly, repeat kneading process.

Divide ball into 2 equal parts, flatten each slightly into round patty, dust lightly with flour, wrap separately in waxed paper, refrigerate 30 minutes.

Ratatouille filling: Heat 1/3 cup olive oil in skillet over medium-high heat. Meanwhile, wash eggplant; dry; dice. When the oil is hot but not smoking, add onion slices; stir until golden and wilted, 4 to 5 minutes. Keep stirring, almost constantly, to avoid burning. Remove with slotted spoon; drain; set aside.

Spread eggplant into hot oil; saute until just lightly crisped and gilded, usually 5 minutes. Eggplant absorbs oil, so add more, tablespoon by tablespoon, as needed. Return onions to skillet; add tomatoes, garlic, sugar, crumbled bay leaf, thyme, about 1 teaspoon salt, 1/4 teaspoon pepper and 1/8 teaspoon cayenne, or to taste. Adjust heat to gently bubbling and cook, uncovered, stirring regularly to encourage evaporation, until it begins to thicken, about 30 minutes. Skim off any oil.

Lightly beat 2 egg yolks in small bowl; whisk into vegetables quickly. Add olives and cheeses. Continue stirring, preferably with wooden spoon, solidifying eggs and melting cheeses to convert it into delicately solid mass. Transfer to large bowl; cool to lukewarm.

Making and baking tourte: Lightly flour pastry board and rolling pin. Unwrap one dough patty from refrigerator; turning it slowly on board, gently pound dough a few times with rolling pin to loosen it and allow it to roll out. If cracks appear, close by squeezing. Keep board well dusted with flour while you roll out dough in quick short strokes to a thin, 12-inch round. Transfer into 10-inch pie pan; trim excess dough. Wrap in waxed paper; refrigerate at once.

Remove second dough patty from refrigerator; repeat operation, but roll this one to a slightly thicker 10-inch round. Place between layers of waxed paper; refrigerate.

Preheat oven to 400 degrees. Prick bottom shell in pan with fork; cover dough with foil, running it up sides and crimping tightly to pinch dough along edge of pan. This prevents dough from shrinking and slipping down. Bake this neatly covered pie shell in center of oven 15 minutes. Remove foil; bake uncovered 5 minutes to dry it out. Next, working fast, fill shell with ratatouille. Top with second dough round; pinch into edge of lower crust around pan. Brush top with glaze of remaining egg yolk beaten with cream. Cut slit in top; slide tourte into center of oven. Bake until top is shiny gold, about 20 to 30 minutes. Cook to lukewarm before serving.