Puffy Omelet with Canadian Bacon Filling

4 eggs, separated
3 oz. Sliced Canadian-style bacon, cut into thin strips
1/4 cup shredded cheddar cheese
1/2 tsp. dried basil
1/4 tsp. white pepper
5 tsp. butter
1/2 cup fresh mushrooms
1/4 cup chopped green pepper
1 large tomato, peeled, seeded, and chopped

Preheat oven to 350 degrees. Beat egg whites until stiff peaks form. Beat egg yolks until thick and lemon colored; stir in Canadian bacon, cheese, half of the basil, and pepper. Fold yolk mixture into egg whites. In a 10-inch skillet with oven proof handle, heat 2 tsp. of the butter over medium heat till a drop of water sizzles. Spoon egg mixture into skillet, gently smoothing surface. Reduce heat to low; cook for 7 to 8 minutes or until the bottom is golden. Bake in oven for 10-12 minutes or until knife inserted halfway between center and outer edges comes out clean. Meanwhile, in skillet cook mushrooms and green pepper in the remaining hot butter over medium heat 3 minutes or until tender. Add the remaining basil and tomato; cook 5 minutes or till liquid is reduced, stirring occasionally. Loosen sides of omelet with spatula. Make a shallow cut across omelet, cutting slightly off-center. Spoon filling over larger half. Tip skillet and fold the smaller portion of omelet over larger half. Slip omelet onto a warm serving platter. Serve immediately.