Steps
1. In a bowl, whisk the eggs with milk, salt, and pepper until well combined.
2. Heat olive oil in a non-stick skillet over medium heat.
3. Add red onion and bell pepper to the skillet; sauté for 2-3 minutes until softened.
4. Stir in cherry tomatoes and spinach; cook for another 1-2 minutes until spinach wilts.
5. Pour the egg mixture evenly over the veggies in the skillet.
6. Cook without stirring for 2-3 minutes until the edges begin to set.
7. Sprinkle feta cheese over the top.
8. Using a spatula, gently lift the edges to allow uncooked egg to flow underneath.
9. When the omelet is mostly set but slightly runny on top, fold it in half.
10. Remove from heat and let it rest for a minute.
11. Meanwhile, toast the whole-grain bread until golden brown.
12. Serve the omelet hot with the toasted bread on the side.