Mushroom and Spinach Frittata

This was part of my attempt to eat healthier, lots of veggies and not too high on the calories.
I picked the recipe up from Cooking Light's website, and made a few changes. The original is here. Unfortunately, this tasted a little too healthy for me, but with enough hot sauce it was filling. Made a good companion for my fried potatoes though. Next time I think I would add more eggs, I prefer more egg to veggie ratio in my frittata.

Ingredients:

• 2  teaspoons  olive oil
• 1/3  cup  chopped Vidalia onion
• 2  cups  sliced mushrooms
• 4  cups  packed baby spinach leaves or torn Swiss chard (I used a package of frozen spinach)
• 2  large eggs
• 4  large egg whites (instead of separating eggs I used 4 whole eggs)
• 1/2  cup  shredded smoked Gouda cheese, divided (I used Swiss since I had it on hand)
• 1/4  teaspoon  salt
• 1/4  teaspoon  pepper
• Cooking spray

Instructions:

1. Preheat oven to 350F.
2. In the olive oil in a medium nonstick skillet, saute the onion on medium high heat for 2 minutes. Add the mushrooms saute 4 more minutes or until tender. Add the spinach until it is wilted.
3. In a medium bowl combine eggs, egg whites, 1/4 of the cheese, salt and pepper. When well mixed add in the mushroom spinach mixture, pour into a greased 8 inch round pan. Top with remaining cheese. Bake for 30 minutes, or until eggs are set.
4. Serves four. I recommend some hot sauce or salsa to go with it.