Wash & prick the skin of the sweet potato & bake in the oven for 1 hour to 1 ½ hours, depending on the size. You want it to be really soft, almost caramelized inside as this improves the flavour. For speed, you can cook in the microwave.
Once cooked, scoop out the flesh & put into a bowl. Add the flour & seasoning & mix until you have a soft dough. You may need a little more flour so that the dough can be easily handled – not too wet & not too dry.
Roll the gnocchi into a long thick sausage shape & if you have time, pop it in the fridge for 30 minutes.
Sauce: This can be made while the gnocchi is in the fridge, or beforehand & then heated when you need it. In an ovenproof dish, put the tomatoes, onion, garlic, oil & seasoning. Cook in a medium/hot oven (around 190c/gas 5) for 20 minutes, until the tomatoes are soft & caramelized.
Pesto: Put all ingredients in a food processor or blender & blitz until a paste forms.
Cook the gnocchi: Cut the gnocchi into 2 inch chunks. You may need a little extra flour. Press a fork into each chunk & then cook the gnocchi.
Lightly oil a non stick frying pan & cook the gnocchi in batches until they are browned each side. Once cooked serve with the tomatoes & the pesto.
Tip: The gnocchi dough will be fine in the fridge for up to 3 days so you can make this in advance.