Place the first 10 dressing ingredients into a large bowl with 8 of the tomatoes, roughly chopped. Mash roughly with a wooden spoon. Leave in the refrigerator overnight to infuse.
The next day, using a ladle, press through a coarse sieve to form a thickish dressing. Finely dice the remaining 2 tomatoes. Finely shred the basil leaves.
When ready to use, heat the dressing gently, whisking well to emulsify. Add the diced tomatoes and basil just before serving.
To make the crust, mix the breadcrumbs with the lemon zest, herbs, garlic and seasoning, then stir in the olive oil until the crumb mixture holds together.
Make horizontal slits in the cod with a sharp knife and insert a piece of prosciutto in each slit. Press the crumbs thickly and firmly on to the top of each fillet. Place, crumb-side up, in a roasting tin and drizzle with olive oil.
Blanch the garlic in milk 3 times, discarding the milk each time. Place the garlic in a small roasting pan, sprinkle with sugar and a drizzle of olive oil and roast until golden.
Heat a little butter in a pan, and quickly wilt the washed spinach. Season lightly.
To serve, set the spinach on serving plates and place the cod on top. Pour the hot dressing around and scatter over the roasted garlic.
© 1995 Kit Chapman. All rights reserved.