Preheat oven to 350 degrees Puree the tomatoes in a food processor. Season with salt and pepper. Divide them equally among 4 ramekins. Chop the fish into 1 inch pieces and fill the ramekins with equal amounts of fish. Pour heavy cream over the fish to cover. Top with a sprinkle of mozzarella and a sprinkle of gruyere cheese. Bake for 15 to 20 minutes.