Preheat the oven to 200°C (fan) / 400°F / Gas Mark 6.
Cut the pumpkin into quarters, remove and discard the seeds and slice off the skin. Cut into chunks and place in a roasting tin.
Peel and slice the carrots and onion, finely slice the celery, and add to them to the tin, along with the garlic cloves, (whole, still in their skins).
Add the oil, rosemary and smoked paprika, season well with salt and black pepper, then toss everything together until the vegetables are fully coated in oil.
Roast for 30 minutes or until the pumpkin and carrots are just soft. Remove from the oven.
Find the garlic cloves, cut off their ends and squeeze the soft flesh back into the roasting tin, discarding the skins. Discard the rosemary stalk.
Tip the contents of the roasting tin into a blender or food processor, (or a saucepan with a hand blender). Add the stock, tomato purée and cream and blitz until completely smooth. Taste and adjust seasoning as required. Serve immediately.
For best results use a cooking pumpkin rather than a large carving pumpkin. The huge carving pumpkins will have very watery flesh which won't give such a rich and creamy soup. Alternatively, a butternut squash would be a perfect alternative to pumpkin.Do a long, slow roast if you can 30 minutes will ensure the vegetables are cooked through, but the longer you leave your veg in the oven at a slightly lower temperature, the sweeter and deeper the flavours will become.Don't forget to take out the garlic cloves before blitzing! (The voice of experience here...!) Remember how many cloves you put in and make sure you fish all of them out of the roasting tin, then squeeze the flesh back into the tin (discarding the skins).