In a food processor, combine flour, salt, and margarine and pulse 10 times. Sprinkle the ice water over the flour mixture and pulse until pastry just begins to come together, about 10 seconds; you should still be able to see small bits of margarine in it.

Transfer the pastry to a work surface, gather it together and pat into a disk. Wrap the pastry in plastic and refrigerate while making the filling.

Heat six tablespoons olive oil in a large non-stick pan. Over medium-high heat, sauté eggplant, peppers, onions, garlic, and thyme until tender, approximately 10 minutes.

Reduce flame to low and cover pan. Cook for an additional 10 minutes, until eggplant is thoroughly softened.

Remove cover and add tomato paste. Cook three minutes longer until liquid has evaporated. Season to taste with salt and pepper.

Pour mixture into a colander or strainer set over a bowl and allow it to drain completely. Discard liquid. Filling can be prepared a day or two in advance and refrigerated.

Preheat oven to 350 degrees Fahrenheit. Grease a nine-inch tart pan with removable bottom.

On a floured surface, roll out dough to a 12-inch circle. Transfer to prepared pan. Press dough into pan, making sure it reaches up the sides of the pan. Trim off any excess dough.

Spread the drained eggplant mixture in the crust.

Lay out alternating slices of tomato and zucchini in concentric circles, overlapping the slices. The slices should completely cover the eggplant mixture.

Sprinkle bread crumbs over the top and bake one hour until crust is golden and zucchini is tender.