In a large bowl beat 6 eggs. Stir in half and half.
In a large skillet, over medium heat, add oil. Then add onions and bell peppers and cook for about 5 minutes or until soft. Remove from heat. Add to egg mixture.
Add asparagus, tomato, and salsa to egg mixture.
Lastly add 2/3rd cup Cheddar cheese and salt and pepper.
Pour egg mixture into each muffin tin about 2/3rd full. Sprinkle the remaining shredded cheese on top of each egg muffin.
Bake in a preheated oven for about 18 to 20 minutes.
Serve immediately or refrigerate for up to 3 or 4 days.