Shrimp & Vegetable Stir Fry

frozen large shrimp, thawed, peeled, and de-veined

stalk fresh broccoli, cut into bite-size florets

small onion, coarsely chopped, about 1/2 cup

red bell pepper, coarsely chopped, about 2/3 cup

large mushrooms, cut in quarters or thick slices

salted butter

Garlic salt, salt, and freshly cracked black pepper,

Sesame seeds, optional