In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add the diced onion, bell peppers, and mushrooms and cook until they're softened, about 3-4 minutes.

Add the minced garlic to the skillet and cook for another 1 minute until fragrant.

Add the chopped spinach to the skillet and cook until it's wilted, about 1-2 minutes. Remove the vegetables from the skillet and set them aside.

In a bowl, beat the eggs and season with salt and pepper.

In the same skillet, add the remaining 1 tablespoon of olive oil if needed and pour in the beaten eggs. Let the eggs cook undisturbed until they start to set around the edges, about 2-3 minutes.

Once the eggs start to set, sprinkle the cooked vegetables evenly over one half of the omelette. Sprinkle the shredded cheese over the vegetables.

Using a spatula, carefully fold the omelette in half, covering the vegetables and cheese. Cook for another 1-2 minutes, until the cheese is melted and the eggs are cooked through.

Slide the omelette onto a plate, garnish with fresh herbs if desired, and serve hot.

Enjoy your homemade Protein-Packed Omelette!