Preheat the oven to 350°F. Take the sausage out of its casing and fry up the pieces in a cast-iron skillet with some olive oil.
Chop the cabbage into fine strips and sweat them off in the pan with the sausage.
Add the diced onion and grated carrot and saute them. Season everything with ground caraway, paprika, parsley, salt, and pepper, take the skillet off the heat, and let everything cool while you prepare the sauce.
Mix the cream cheese, eggs, flour, and shredded mozzarella, then season the mixture with nutmeg, salt, and pepper. Pour the sauce over the veggies and sausage in the skillet.
Cover the frittata with the onion slices and olives, sprinkle shredded mozzarella on top, and bake in the oven for 40 minutes.