Preheat your grill on medium
Melt the butter in a large frying pan or pot (which can be safely put under the grill) and fry the red onion for about 2 minutes till it starts to soften.
Add the garlic and peppers and stir, then cook for 2 minutes.
Add the tomatoes, season with a little salt and pepper, and allow to cook for about 5 minutes until the tomatoes begin to soften.
Pour over the wine and simmer for 10 minutes.
Meanwhile, cook the gnocchi according to the package instructions.
Stir in the creme fraiche and basil and stir well, then mix in the cooked gnocchi.
Tear up the ball of mozzarella with your fingers and scatter over the gnocchi.
Place under the grill for 5-10 minutes until the cheese is starting to turn golden.
Scatter over some extra fresh basil and serve with a big green salad.