It's crunch time!

With spring in the air and summer around the corner, what better way to welcome them than with a dish that celebrates the glory of vegetables. Yes, there is a bit of work involved, but it is well worth the effort, and two of the three recipes set out here - the olive purée and the tomato fondue - can be made in large quantities, since they keep very well and have a wide range of uses. The other recipe uses up every part of the courgette and aubergine - the skins are used to line the moulds while the flesh goes into the filling.

This recipe calls for six standard sized ramekins, but these can be replaced by whatever is available. It could be made in a larger mould or even a small spring-form cake tin, which would look pretty impressive at the table. (Though, obviously, if you go for a bigger mould, the strips of skin used to line it will need to be longer, so you'll have to buy big courgettes and not cut the aubergines in half.)

This recipe can be used as a blueprint for other vegetables, too, depending on the time of year and your taste. It is fabulous on its own, but if you fancy a bit of protein alongside, it makes a wonderful garnish to a leg of lamb - slow-roasted, of course.

Recipe serves six.

6-8 medium courgettes, nice and green
2 large aubergines
Olive oil
2 shallots
1 clove garlic
4 red peppers
1 small bunch fresh thyme
6 tbsp tomato fondue (recipe follows)
6 dssp olive purée (recipe follows)
Salt and pepper

Wash the courgettes well, cut off the tops and bottoms, then peel, taking care to keep the strips intact because these will form the outside of the moulds, along with the aubergine skin. Bring a pan of water to the boil, blanch the courgette strips in it for one minute only, then remove at once and place in iced water to stop the strips from cooking any further.

Cut the courgette flesh into small dice, sauté gently in olive oil for three to four minutes, then tip into a sieve placed over a bowl, to collect the excess oil. Season and set aside.

Top and tail the aubergines, cut them across in half, then peel off the skin as per the courgettes, and cook in exactly the same way. Dice the aubergine flesh and put to one side.

Peel and finely chop the shallots and garlic. In the same frying pan, sauté these in another tablespoon of olive oil, along with the reserved oil drained from the courgettes. After three to four minutes' cooking, add the aubergine dice and cook on a medium heat for 15-20 minutes. Drain off any excess oil, again reserving it, then purée the mix, either in a liquidiser or by rubbing it through a fine sieve. Season well, then set aside.

Top and tail the red peppers and remove the core. Cut the peppers into quarters so that you have four relatively flat rectangles of pepper. Heat the grill, line the grill tray with tin foil and oil the peppers. Place the peppers skin-side up under the grill, and cook until the skin blackens. Please be patient - they need to stay there until they look burned. When nicely blackened, remove from the grill and peel off the charred skin by hand under cold running water. Once peeled, set aside.

Next, the best job of the lot - pick the thyme leaves and set aside. Unfortunately, this can't be avoided because the stalks are tough and not pleasant to eat. Once that's done, you're ready to assemble your charlottes. (You will, of course, have already made the tomato fondue and the olive purée recipes below.)

Brush the inside of the ramekins all over with the oil reserved from frying the aubergines, then line the inside with alternate strips of the blanched courgette and aubergine peel - these should be long enough to hang way over the edge. Now fill up the ramekins with alternate layers of aubergine purée, red pepper, diced courgette, tomato fondue and olive purée, seasoning with salt and pepper and sprinkling with thyme as you go. Press down the filling regularly as the charlottes are being built up.

Carry on layering until the ramekins are filled to about half a centimetre above the top, then fold back over the strips of courgette and aubergine.

Now you're ready to finish off the dish. Preheat the oven to 150C/300F/ gas mark 2. Make up a simple tomato sauce by taking a couple of tablespoons of tomato fondue, liquidise with a little water, and pass through a sieve. Stir in a little of the oil from the fondue.

Bake the filled ramekins for 15 minutes. Remove from the oven and turn out - hold the ramekin in one hand with an oven glove, place a small plate on the top, tip over and shake gently back and forth.

Sprinkle the charlottes with rock salt and freshly cracked black pepper, pour a little sauce around or over, and serve with the remaining sauce in a jug.

It is essential to use only top-quality ripe tomatoes when making this - it really isn't worth the effort if you use sub-standard raw materials. While you're at it, it might be an idea to make up a big batch of this fondue, using, say, a kilo of tomatoes instead of the amount listed here - it will keep well in the fridge for a good week, and can also be frozen. The fondue has many uses, ranging from a pasta or risotto sauce to enriching a stew, or as the base for a great ratatouille.

1 onion, peeled and finely diced
125ml extra-virgin olive oil
1 heaped tsp coriander seeds
2 cloves
1 star anise
2 cloves garlic, peeled and minced
1 bouquet garni, comprising thyme, celery leaf, parsley and rosemary
250g best-quality fresh tomatoes
1 dssp tomato ketchup
1-2 drops Tabasco, to taste
2-3 drops Worcestershire sauce, to taste
25ml sherry vinegar

In a frying pan over low heat, sweat the onions in the olive oil for 10-15 minutes, along with the coriander, cloves and star anise. Add the garlic and bouquet garni and cook for five minutes more. Meanwhile, bring a large pan of water to the boil and, once bubbling, drop in the tomatoes for 10 seconds. Remove at once, then plunge them into ice water and peel - the skins will come off quite easily. (If any do not, put the tomato back into the boiling water for a few seconds more. Be careful not to over-blanch them, otherwise they will start to break up.)

Once peeled, cut the tomatoes in half and, with a small spoon, scoop out the seeds. Place these in a sieve set over a bowl and sprinkle lightly with salt - this will draw out precious juices, which, incidentally, have more flavour than the flesh. Chop up the tomato flesh.

Add the tomato dice and juice to the onion pan. Add the ketchup, Tabasco, Worcestershire sauce and the sherry vinegar, and cook on a low heat for four hours. If it looks as if it's reducing too quickly and is in danger of catching, add a little water. When done, the fondue should be dark and almost jam-like, and the oil will have split from the sauce, so you may have to cook it a little longer.

Olive purée

This is a simplified version of the classic French olive paste, or tapenade. As with the tomato fondue, it has myriad uses: stir into a risotto or pasta, use as a dip for bread or fresh vegetables, or as an accompaniment to meat such as duck or chicken - it really is that versatile.

100g stoned black olives
20 fresh basil leaves
1 tbsp extra-virgin olive oil
Lemon juice, to taste

Purée everything thoroughly in a liquidiser. That's it.

· Heston Blumenthal is chef/proprietor of The Fat Duck, Bray, Berkshire (fatduck.co.uk).