Heat the olive oil in a deep sided skillet or pot (6-quart capacity) over medium heat
Brown the sausage on all sides, and set aside
Sauté the onion and garlic, seasoning lightly with a touch of salt, until translucent
Add the wine, chicken stock, tomato paste, anchovy paste and whisk until combined
Stir in the mussels, cover the pot, and steam for about 5-6 minutes, or until all the mussels have opened
Discard any unopened mussels
Garnish with parsley and serve immediately with crusty bread or pasta.