Pre-heat your oven to 200C Fan/425F/Gas Mark 7
Heat up the oil in a large saucepan on a low heat, chop up the onion, pepper and garlic and add them to the saucepan. Cook for around 5 minutes until soft
Then add the spinach and cook until it all wilts down
Add the chopped tomatoes, tomato puree, mixed herbs and salt. Bring to a gentle simmer
While the sauce is simmering, bring some water to the boil in another saucepan and add the gnocchi, check the pack for instructions, but most gnocchi takes 2-3 minutes to cook and it's done when it rises to the surface of the water
Drain the gnocchi and mix it into the sauce, then pour the whole lot into a large baking dish
Tear the mozzarella up and arrange over the top, then add the grated cheddar all over
Cook in the oven for 15-20 minutes, or until the cheese is golden all over and the sauce is bubbling
Serve immediately, or allow to cool fully and store in the fridge for 2-3 days. It can be reheated either in the microwave, or in the oven