This may not be the exact way that you remember it, but this was about the closest that I have found. Maybe you can adjust things to your tastes from there. I hope this helps.

Fajita Frittata

1 tablespoon butter or cooking oil
1/2 cup thinly sliced green pepper
1/2 cup thinly sliced onion
1/4 to 1/2 teaspoon chili powder
1/4 teaspoon ground cumin
1/2 cup chopped tomato
4 eggs
1/4 cup water
1 medium tomato, sliced
2 tablespoons shredded mozzarella cheese
Salsa, optional
Sour cream, optional

In 10-inch omelet pan or skillet (with ovenproof handle), over medium heat, heat butter until just hot enough to sizzle a drop of water. Add pepper, onion, chili powder and cumin. Cook, stirring occasionally, until pepper is soft and onion is translucent, about 3 to 4 minutes. Add chopped tomato. Continue cooking 1 additional minute. Remove from heat. Set aside.

In medium bowl, beat together eggs and water until blended. Pour over vegetables. Cook over medium heat until eggs are almost set, about 6 to 8 minutes. Top with tomato slices. Sprinkle with cheese.

Broil about 6 inches from heat until cheese is melted and eggs are completely set, about 1 to 2 minutes. Cut into wedges. Serve with salsa and/or sour cream, if desired.