Preheat oven to 350℉.
In a 10-inch cast iron skillet over medium heat, melt 2 tablespoons butter and 2 tablespoons olive oil.
Once butter is melted, add 1 cup diced onions, 2 minced garlic cloves, and 1 cup diced peppers. Cook until peppers and onions are softened, about 5 minutes.
To the skillet, add 4 cups collard greens. Stir until wilted. Season with salt & pepper.
In a separate bowl, whisk together 12 eggs and ½ cup cream. Season egg mixture with salt & pepper. Add optional hot sauce.
Pour egg mixture over vegetables in the skillet. Sprinkle 8 ounces crumbled feta over egg mixture.
Bake in preheated oven about 30 minutes or until eggs are set. Remove from oven and sprinkle with 2 tablespoons parsley.
Cut into wedges and serve hot.