For 6 portions you need
3 whole medium sized white onions
60ml extra virgin olive oil
Approximately 50g (half a small jar) anchovies preserved in oil
Optional: 50ml chopped flat leafed parsley
Optional: a few shaving of Parmesan
Pasta: use the thick Venetian Spaghetti, Bigoli, if you can find it. Otherwise a good quality tagliatelle or tagliarini will be perfect. As the sauce is rather beige I would use either butternut or spinach flavour to add interest and colour
400g dry pasta for 4 medium portions
To Prepare the sauce
Set oven at 180°C
Place the whole, unpeeled onions on a baking tray and roast them for 40 minutes.
An option is to finely slice the onions and cook them gently, not allowing them to brown, until they are very soft.
Peel the roasted onions.
Place 2 onions into the bowl of a blender or a food processor.
Add the anchovies and olive oil to the onions. Blitz for a few seconds until the mixture is smooth and creamy. If necessary at more olive oil to achieve a consistency of cream. This can be done hours in advance.
Slice and dice the remaining onions into approximately 10mm pieces.
Stir the chopped onion into the above sauce and heat just before serving.
Cook the pasta in boiling salted water until it is al dente (just cooked, tender but firm to bite)
Drain the pasta, retaining approximately 40ml of the cooking water. Add this water and the sauce to the cooked pasta, toss and serve.
As this is a rather dull “beige” sauce finish the fish with a sprinkling of chopped Italian (flat leafed parsley) and a few shavings of Parmesan