Sweat onions and garlic in butter and oil, cook - 45 mins - with lid on until very soft and sweet.
Turn up the heat to high and boil away the liquid until it begins to fry, add the tomato paste and cook stirring for 5-6 mins then add the rest of ingredients - except the basil - and blitz until slightly chunky or smoother if you like then simmer slowly for 2 ½ hours over a low heat adding more water if it dries out too fast.
When done remove from heat stir in the basil and a pepper and infuse with the lid on for 20 min then use or keep in the fridge for 2 days or freeze until needed.
I added the mussels 5 minutes before cooking time was done.
This gives enough time for the fresh mussels to open. Discard any mussels that do not open.
When mussels are cooked, add chopped basil, place lid back on and allow to infure for 10 minutes before serving.
Serve with buttery warm ciabatta!Reprinted with permission from Easy Cooking. To see more recipes, click here.