Heat olive oil in a 34 cm paella pan or large shallow pan. Brown sausage for about 3 to 4 minutes. Remove and set aside.
Saute onions, garlic, tomatoes, and bell pepper for 3 minutes.
Add rice and stir fry for another 3 minutes.
Pour in white wine and chicken stock.
Crumble in the saffron. Season with salt and pepper. Cover, reduce heat and allow it to simmer for 12 minutes.
Preheat oven to 350°F (180°C).
Return browned sausage to the pan. Layer salmon, shrimp, and mussels around the pan.
Cover and cook for 6 minutes.
Remove lid and transfer pan to the oven. Bake uncovered for 10 minutes to finish cooking.
Remove from oven and let it sit on stove top for 10 minutes.
Serve with chopped parsley and lemon wedges.