Preheat broiler to high. In a 12 inch oven safe non stick pan cook down spinach with butter, onion and garlic powders over medium low heat. While spinach is cooking down beat eggs with milk and and seasoning salt. Fold in grated cheese and pour into pan with cooked spinach. Raise heat to medium and cook for approximately 4 minutes until almost set. Place in broiler for 2-4 minutes until completely set. Color will be golden brown. Garnish with red seedless grapes for a light delicious breakfast. If you prefer a thicker Frittata, you can use a 9 inch pan and raise the stovetop and broiler times by approximately 1-2 minutes.
* I prefer grating the cheese myself as opposed to store bought grated cheese. The reason being that pre-grated packaged cheese tends to be drier and lacks the creaminess of freshly grated cheese.