Heat oil or butter in large ovenproof skillet (I like cast iron) over medium-high heat. Sauté mushrooms until browned. Add the onions and red pepper, sauté until tender.
Add the potatoes, season with 1-2 tsp. Steakhouse Seasoning, sauté to warm the potatoes and crisp slightly, reduce heat. Add sausage. In a medium bowl, whisk eggs, cream and 1 tsp. Steakhouse Seasoning; pour over mixture in sauté pan. Cook 4 to 5 minutes until eggs are just set. Sprinkle cheese over frittata and place in oven. Cook until cheese is melted and eggs are completely set. Let frittata stand for a few minutes before serving.