Beat the eggs with the yogurt and a pinch of salt and pepper.
Add half the parmesan to the eggs and mix lightly to combine.
Thinly slice the onions and bell peppers.
Turn the oven on to 390°F (200°C or 180°C fan) and let it preheat so that you can finish the frittata in the oven.
To a cast iron pan, over medium-high heat, add 1 tbsp of oil. When the oil is hot, add the sliced onions and bell peppers. Cook them for about 4-5 minutes, stirring occasionally, ensuring they don’t burn.
Take the sausages out of the casings and break them up into smaller pieces with your hands. Turn the heat on the cast iron pan to high, move the peppers and onions to one side, and start adding the sausages to the pan.
Cook for about 10 minutes, stirring from time to time, making sure the sausage browns but doesn’t burn and making sure the onions and peppers don’t burn. If they start to burn, turn the heat down a bit.
Add the minced garlic and saute for about 1 minute.
Turn the heat down to medium, and add the beaten eggs, mixing them with the sausage, peppers, and onions.
Add the goat cheese in little chunks, chopped parsley, and top with the remaining parmesan.
Finish it in the preheated oven at 390°F (200°C or 180°C fan) until golden and cooked through) (about 13-15 minutes). The exact timing will vary based on your oven, the thickness of the frittata, and the ovenproof pan or baking dish you’re using. It took me about 13 minutes for this frittata. You’ll know it’s done when the edges look golden brown, and the center is set/not jiggly (as shown in the step-by-step picture).