Breakfast Potato Sausage and Egg Skillet

ground Italian sausage

medium yellow onion (minced (about 3/4 cup))

large eggs

fresh minced parsley (or chives)

grated colby jack cheese (divided)

whipping cream

salt

medium potatoes (about 12 oz)

butter to dot the top (plus more to butter dish)

An oven proof baking dish such as a deep pie dish or cash iron skillet (should hold 3-4 cups.)