Cook bacon until fat is rendered. Set aside bacon and fat.
Cook onions and garlic in bacon, until soft.
Add mushrooms and spinach. Cook down.
Add steak and bacon. Cook until all come together. Remove from heat.
In large bowl, combine eggs and cream. Whisk well.
Add cheeses.
Place meat and veggies in bottom of pie crust.
Pour egg, milk and cheese mixture over meat and veggies.
Bake at 375 degrees for 45 - 60 minutes (until fork comes out clean and center is set).