Preheat the oven to 400 degrees
Line a large sheet pan with foil or parchment paper; set aside.
In a large bowl, mix the passata, oil, salt, red pepper flakes, oregano and pepper.
Scatter the peppers and onion across the sheet pan in a single layer. Add the sausage meat and break it up into chuncks.
Scatter the gnocchi across the sheet pan.
Pour the sauce over everything; mix to coat and finish with everything in a single layer.
Bake in the oven for 15 minutes then give everything a stir and sprinkle mozzarella chunks over top and put back in the oven to cook another 10 minutes, or until the mozzarella is melted and peppers are soft.
Remove sheet pan from oven and sprinkle with paremsan and fresh basil. Serve.