Cut peppers in half.
Remove seeds; slice into thin strips.
Peel tomatoes; cut into eighths.
Clean zucchini; cut into 1/2 inch thick slices.
Heat oil in large frypan or Dutch over.
Add all vegetables; cook about 10 minutes, stirring occasionally.
Trim fat from steak.
Lightly grease ovenproof casserole; place 1/3 of vegetable mixture in dish.
Arrange steak on top.
Sprinkle with salt, pepper, and basil.
Cover with rest of vegetables.
Pour wine over vegetables; cover casserole.
Cook in preheated 350Â°F oven 50 minutes.
Ten minutes before end of cooking time, remove cover to reduce liquid.