Ham and Mozzarella Frittata

I have always wanted to make a frittata, but for some reason, I was too intimidated. I can't imagine why, because it is super easy and quick. The only irritant was that it needs to be watched so that it doesn't burn under the broiler, but that is small considering the whole meal too about 15 minutes from start to finish! I am now thinking of how many combinations I could come up with to make more of these easy meals! If only I could get my husband on board with eating breakfast for dinner!

Loosely adapted from: http://picky-palate.com

Ingredients:
1 tbsp butter
1/2 c onion
1 c chopped ham
6 large eggs
1/2 tsp salt
1/4 tsp black pepper
1/4 c milk
1/2 c mozzarella cheese

Directions:
Preheat oven's broiler. In a skillet sprayed with cooking spray(I used cast iron) heat over medium heat and add butter. When hot, add the onions and saute until soft about 5 minutes.
Add the ham and cook for an additional 3 minutes.
In a small bowl, whisk the eggs, salt, pepper and milk until combined. Pour into hot skillet and cook for 3-5 minutes, pushing the sides down with a rubber spatula. Top with the cheese and place under the broiler. Watch carefully; broil for 3-5 minutes or until golden and puffed around the edges. Remove and let cool before cutting into wedges.