This recipe is very flexible.  It is called an Improbable Quiche, because it doesn't have a crust.  This was originally a Bisquick recipe and I don't usually have Bisquick, so I use the Bisquick substitution.  It's so flexible.  In the first column you can see the original recipe and in the second is a vegetarian version which I made and was terrific.  Great for a light supper with a salad and also a wonderful breakfast or lunch, cold or heated.  

Ingredients:
12 slices of bacon - fry crisp, crumbled (may use leftover ham, etc.)
1 cup shredded swiss cheese
1/2 cup finely chopped onion
2 cups milk
1/2 cup Bisquick
4 eggs

Ingredients:
1/2 cup finely chopped onion
1/2 cup coarsely chopped mushrooms
​1/2 cup coarsely chopped sun-dried 
         tomatoes
2/3 cup feta cheese
2 cups of milk
2 eggs & 2 egg substitutes
1/2 cup Bisquick substitute
​   (1/2 cup flour, 3/4 teaspoon baking powder 1/8 teaspoon  salt, & 1/2 Tablespoon melted butter or oil.)

Heat oven to 350 degrees
Spray a  9-10 inch pie pan with cooking spray.
Sprinkle bacon, cheese onions every on pie plate
Combine other ingredients well
Pour over bacon mixture
Bake until golden brown and knife in center comes out clean.
  ( about 50-55 minutes)
Let stand 5 min before cutting.
 Refrigerate leftover (can be prepared ahead of time 

The first two instructions are the same. - preheat the oven and spray the pie pan.
     I like to sauté the onions and mushrooms for 3-4 minutes, which is what I did before I sprinkled it on the pie plate along with the feta cheese and chopped sun-dried tomatoes.
      Then I beat the 2 eggs together and whisked in 2 egg substitutes.  Whisked in milk and baked for 50-55 minutes.