- In a large bowl, beat eggs until frothy;
- Stir in corn and salt; set aside.
- In a large skillet, melt butter over medium heat.
- Add onion; sauté until lightly browned, about 3 minutes.
- Add egg mixture; cook and stir gently until mixture begins to set, about 2 minutes.
- Stir in cheese; cook and stir until eggs are firm, about 3 minutes longer. Remove pan from heat.
- Fold in avocado and transfer to serving platter.
- Serve with warm tortillas, if desired.