Preheat oven to 350 degrees, place sheet pan on middle rack.
Butter large oval cast iron baking dish. arrange sliced sausage in dish and cover with grated cheese.
Prepare Royale in glass 2 cup measuring cup. Break 4 eggs into cup, fill to 2 cup mark with cream, and add seasonings, whisk gently until completely mixed.
Pour royale over cheese and sausage. Strike pan sharply on counter several times to remove air pockets.
Place into preheated oven on sheet pan. Check in 20 minutes, rotate pan if rising or browning unevenly. Visually check progress through oven window every 5 minutes thereafter until quiche is puffy and golden brown. Total cooking time is 30 -35 minutes.
Remove from oven to cool gently on trivit or slice and serve immediately.
To store allow to cool completely, slice into 6 pieces and store in ziplock bag in refrigerator.