In a large dutch oven or other large pot, saute your onion in a little bit of olive oil until translucent, about 8-10 minutes. Add garlic and stir to incorporate cooking for a minute or so. Add tomatoes, tomato sauce, wine, spices and sugar and simmer for about 30 minutes to let the flavors combine and let the sauce cook down and get thick. Add the mussels to the pot and stir to cover in the sauce. Cover and continue to cook for 10-12 minutes until mussels are cooked through and have opened up.Serve in a shallow bowl with thick slices of garlic bread to soak up the sauce.
Sambuca is an Italian liqueur that has a licorice flavor. It gives a wonderful depth to this dish as it adds a bit of sweetness and anise flavor without using fennel. If you don't have any or don't like licorice don't use it.