Zucchini, tomato and cheese pie

1 1/2 lb zucchini
Salt
3 md ripe tomatoes
4 tb butter
1 tb oil
3 eggs, separated
2 c Swiss cheese, grated
1/2 c Feta cheese
freshly ground pepper
1 tb fresh basil, chopped or mint

1. Wash the zucchini, trim, and cut into 1/4 inch slices. Salt, drain, and pat dry.
2. Meanwhile, peel the tomatoes, halve horizontally, and remove the seeds. Heat 2 Tbs. butter with the oil in large saute pan. Lightly brown the zucchini on both sides; drain on brown paper. Lightly brown the tomatoes until they soften slightly but do not become limp. Cool.
3. When you are ready to assemble the pie, beat the egg yolks, set aside. Place half the zucchini in 9 x 12 inch dish. Sprinkle with 1/3 of the grated Swiss cheese and half the Feta cheese, dot with 1 Tbs. butter, and sprinkle with salt, pepper, and half the basil or mint.
4. Beat the egg whites and fold into the yolks. Spread half of this mixture over cheeses. Slightly flatten the halved tomatoes, and arrange across the pie. Sprinkle with 1/3 of the Swiss cheese, half of the Feta cheese, and the remaining basil or mint. Top with the remaining zucchini slices, and season with salt & pepper. Spread with remaining egg mixture, top with the remaining Swiss cheese, and dot with remaining Tbs. butter. Bake in a preheated 400 oven for 25 - 30 minutes or until the eggs are set.