Begin by making the tomato sauce. Put 150g very finely sliced onion into a saucepan with 1 tbsp olive oil and let it sweat slowly over a low-medium heat for around 15 minutes until it's soft (do not allow it to colour). If it looks as though it might catch, add a splash of water to the pan
Add 500g large, ripe tomatoes, 1tbsp tomato paste and season with salt. Leave to simmer over a low heat for about 45 minutes, until the tomatoes are thick and rich, adding a little water if the level of the liquid gets too low. Remove from the heat
Put 1/2 tbsp oil oil in another pan with 1 chopped clove of garlic and cook over a low-medium heat. When it's almost golden brown, add 10g basil leaves and stir. Pass the oil through a sieve into the cooked tomato sauce
Whisk the sauce to break up the tomatoes. If it's too thick, thin it with a little water, ideally some pasta cooking water. Pass the sauce through a wide-holed sieve resting over a bowl, and use the back of a ladle to extract the smooth mixture. I added 1tbsp homemade red pesto.
Check the seasoning and add more salt if necessary
Preheat the oven to 200°C/gas mark 6
Blanch 60g frozen peas in boiling water for 30 seconds, then drain well
Put 2 baby squid (keep the tentacles) and 1 (boiled) egg white into a food processor and pulse until they are roughly chopped. Add 100g diced romano peppers, the blanched peas and 5g chives and continue to pulse until you have a coarse mixture
Use this mixture to stuff 4 baby squid, keeping some space free at the top. Place a piece of the tentacles at the end of the filling and close the calamari with a rosemary sprig or a toothpick
Trim the other end of each calamari to create a tiny hole and keep the filling from bursting out when cooking
Heat a large heatproof baking dish over a medium heat and fry a garlic clove in 1 tbsp of olive oil. Add the calamari and fry for a couple of minutes until browned, then pour in 50ml white wine and let it evaporate over a medium-high heat
Add 200ml of the tomato sauce and 100ml fish stock, then transfer to the oven for 20 minutes. You can check the filling is cooked through by sticking a toothpick in the centre of the filling; it should feel hot when you touch your lips. Serve immediately
(Here Francesco Mazzei's original recipe)