For instance

• 1/2 medium onion, diced (1/2 cup)
• mushrooms (1 cup)
• 1 1/2 cups diced cooked sausage-like product

• 2 large eggs
• 2 large egg whites
• 1/2 cup all purpose flour
• 1/2 tsp baking powder
• 1/4 tsp salt
• pinch cayenne pepper
• 1 1/3 cups milk (low fat is fine)
• 1/4 cup grated Parmesan cheese

1. Preheat oven to 400F.
2. Lightly grease a 10-inch quiche/tart pan (or a 9-inch pie plate)
3. Prepare Stuff. For instance, in a medium frying pan, cook onion and mushrooms with a bit of vegetable oil (or cooking spray) over medium-high heat until onions are translucent and tender, and mushrooms are browned. Set aside to cool for a few minutes. Add sausage-like bits.
4. In a large mixing bowl, whisk together eggs, flour, baking powder and salt. Whisk in milk, then stir in Stuff mixture.
5. Pour quiche base into prepared pan. Top with Parmesan cheese.
6. Bake for 25 minutes (30-35 minutes in a pie plate), or until center is set and the outside edge is golden brown.
7. Let set for 5 minutes, then slice and serve.

Adapted from http://bakingbites.com/2009/03/sausage-and-mushroom-crustless-quiche/