In a large skillet, heat oil and brown the onion on medium heat for about 2 minutes. Add peppers and cook for another 2 minutes.
Meanwhile, in a bowl, whisk eggs with the Parmesan, garlic, and pepper.
Pour egg mix into the skillet. Cook on medium-low until the eggs are cooked (10–15 minutes). If the frittata is still runny on top, you can either flip it or broil in the oven for a couple of minutes.
Allow the frittata to cool briefly, then slice into quarters and place each quarter inside a kaiser roll (add slice of cheese first, if desired). Top with a lettuce leaf and close sandwich.
- 15 ml (1 tbsp.) olive oil
- 1 onion, chopped
- 1 red pepper, diced
- 8 eggs
- 60 ml (¼ cup) Parmesan cheese, grated
- 1 clove garlic, minced
- 4 whole wheat kaiser rolls
- 4 lettuce leaves
- Optional: Top sandwiches with thin slices of cheese.