1. Heat the olive oil in a paella pan or large frying pan and add the onion, green pepper and half the paprika. Cook over a medium to high heat for 20-30 minutes, stirring occasionally.
2. Meanwhile, prepare the artichokes: cut off the stalks from the base. Carefully snap or pull off enough layers of the tough, green outer leaves until you reach the ones that are mostly yellow and therefore tender. Cut the tips off these, then peel the tough green outside of the base of the artichoke, using a potato peeler or sharp knife, until you see yellow. Scrape out all the furry choke inside the artichoke with a teaspoon.
3. Cut each artichoke in half and each half into six wedges. Add these, along with the garlic and rosemary, to the softening onion and peppers. Fry for a couple of minutes, then cover with foil or a lid and cook for a further 8-10 minutes over a medium heat, stirring every now and then.
4. Bring the vegetable stock to the boil and add the saffron, mushrooms and tomato purée to infuse.
5. Over a medium heat, add the rice and remaining paprika to the vegetables in the pan. Stir the rice thoroughly for two minutes before adding the stock mixture.
6. Bring to the boil and at this point take the time to season the liquor adequately with salt and freshly ground black pepper.
7. When the rice appears above the stock, don't be tempted to stir it: just turn down the heat to low to prevent it sticking to the bottom of the pan. Continue cooking for another 5-10 minutes until 80 per cent of the stock has been absorbed into the rice.
8. Remove from the heat. Scatter the strips of pepper evenly over the top of the paella and cover the pan tightly with foil before letting it rest for 10 minutes.
9. Take off the foil, sprinkle with the parsley and serve with the wedges of lemon.