Pre-heat the oven to 375°F and place a rack in the middle of the oven.
Peel and finely chop the onion.
Wash the red pepper, cut in half and remove the seeds and stem. Slice thinly and then chop as finely as possible.
Crack all of the eggs into a large bowl. Add the salt, pepper and any other herbs or spices. Whisk well.
Lightly grease a non-stick 12-slot muffin tin with olive oil, butter or coconut oil. Also spread a bit of oil across the surface of the tin so that any spill over won't stick.
Equally portion the onion, red pepper, spinach, chili and bacon into the muffin tin slots.
Carefully pour the egg mixture into each muffin slot leaving a bit of room from the top. Pour less than needed in each one to start and top up with whatever is left over.
Top each mini quiche with the granted cheese.
Cook for 15-18 minutes. Check with a fork or meat fork to see if the quiche is dry in the middle. If it's still a bit moist you can removed them from the oven as the quiches will continue to cook for a few more minutes.
Let cool 5-10 minutes and carefully remove from the tin. Use a silicon or rubber spatula to not scrape the non-stick pan.
How Many Mini Quiches Should You Eat?
This depends on more factors than I could list here, but here are my simple guidelines:
If you weigh less than 120 lbs you might find one or two quite filling.
For most people two would be about right.
For a bigger guy, someone who is highly athletic, three or more.