Preheat oven to 350° F.
Remove casings from sausages and cook in skillet, breaking up into small pieces, until no longer pink about 5 minutes. Remove sausages from pan and drain off fat.
In the same skillet melt butter over medium-high heat. Cook onion, garlic, zucchini and red pepper until softened.
Combine vegetable mixture with sausage and spread into a greased 9" quiche dish or pie plate. Sprinkle with Cheddar.
In a bowl, beat eggs with milk and seasonings. Pour evenly over filling in pan. Bake for about 25 minutes, or until center is set. Cut in wedges to serve.