01 - Set the oven to 350°F (180°C) for baking.
02 - Heat olive oil in a 10-inch ovenproof skillet over medium heat and cook the sausage for 2-3 minutes until lightly browned, then remove and set aside.
03 - Using the same skillet, cook diced red bell pepper and zucchini for 3-4 minutes until softened, then add spinach and spring onions and cook another 1-2 minutes until wilted.
04 - In a large bowl, whisk together eggs, heavy cream, salt, black pepper, and smoked paprika, then fold in cheddar and Parmesan cheeses.
05 - Return the cooked sausage to the skillet with vegetables and spread the mixture evenly across the pan.
06 - Pour the egg and cheese mixture over the sausage and vegetables and tilt the skillet to distribute it evenly.
07 - Cook the mixture on medium heat for 2-3 minutes until the edges begin to set.
08 - Transfer skillet to the preheated oven and bake for 15-18 minutes until the center is just set and slightly puffed.
09 - Allow the dish to cool for 5 minutes before slicing; garnish with fresh basil or parsley and serve warm.