Preheat your oven to 180C/Fan 160C/Gas 5. Line a roasting tin with greaseproof paper. Slice the tomatoes into about 8 wedges each. Scatter to tomatoes onto the roasting tin and sprinkle with salt and pepper. Slide into the oven and cook for 20 mins.
Meanwhile, peel the onion and finely dice. Peel the garlic clove and crush or finely chop. Halve the chilli, flicking out the membrane and seeds for less heat. Finely chop the chilli.
Pour 1 tbsp oil into a pan and warm to a medium heat. Slide in the chopped onion, garlic and chilli. Sprinkle in 1 tsp dried oregano and a little salt and pepper. Fry for 3-4 mins, till slightly softened.
Pour 750ml boiling water into the pan. Crumble in the stock cube, and stir well till dissolved. Bring to the boil. Slide in the gnocchetti. Simmer for 8-10 mins, till the pasta is tender with a slight bite.
While the pasta is cooking, finely chop the parsley.
The tomatoes should be roasted by now. Transfer to a chopping board and slice them roughly into small pieces. Add the chopped tomatoes to the soup. Sprinkle in the flat leaf parsley. Squeeze in half of the lemon juice.
Taste the soup and add more salt and pepper if needed. Ladle into bowls and serve.