Ingredients:

(Serves 4)

1kg ripe, plum tomatoes

About 3tbsp olive oil

1tsp fennel seeds

1 large onion, diced

2 large garlic cloves, sliced

150ml full-fat creme fraiche (half-fat will split during cooking)

A large handful of summer herbs, roughly chopped (dill, basil and parsley)

Salt and pepper to season

Grating of Parmesan or vegetarian hard cheese to serve

For the potato gnocchi:

500g potatoes, peeled

250g plain flour

1 medium egg, beaten

Salt

1. Heat the oven to 180C/fan 160C/gas mark 4.

2. Halve the tomatoes lengthways and put them, cut-side down, in an oiled roasting tin. Sprinkle with most of the oil and the fennel seeds and season with salt and pepper. Roast for one hour, turning the tomatoes over halfway through cooking. When cool enough to handle, cut each tomato into smallish pieces with scissors.

3. Meanwhile, in a large frying pan, fry the onion gently in one tablespoon oil for four to five minutes until soft. Add the garlic and fry for a further minute, then set aside.

4. For the gnocchi, boil the potatoes in salted, simmering water for 20 minutes or until tender. Drain, mash, taste and season well. Mix in almost all the flour and the egg. Flour your hands and knead into a ball. Using more flour to prevent sticking, roll out into long batons 2cm thick. Cut these into 2cm pieces. See the 'Tip' below if you want to give them a traditional gnocchi shape.

5. Cook the gnocchi for exactly three minutes in boiling water, then drain and spread out on a clean tea towel, separating them to prevent sticking.

6. Now back to the sauce: Tip the tomatoes and their juices into the onion pan and add the creme fraiche and herbs. Very gently, combine until everything is evenly distributed. Check the seasoning, then stir the gnocchi into the sauce and serve with the Parmesan.

Prue: My All-time Favourite Recipes by Prue Leith is published by Bluebird, priced £25.