Preheat the oven to 425 degrees. \nRemove the casings from the sausage and crumble into small chunks. Add to a large mixing bowl along with the gnocchi, garlic, peppers, onion, tomatoes, 3 Tablespoons olive oil, Cuba spice, and 1 teaspoon kosher salt and a pinch of crushed red pepper flakes, if using. Toss to combine. Spread in an even layer on a large, rimmed prepared baking sheet. \nTransfer to the oven and roast, tossing once halfway through, until the sausage is cooked through, veggies are tender and tomatoes begin to burst, about 25 minutes. \nRemove baking sheet from the oven and turn the oven to broil. Sprinkle the entire baking sheet with mozzarella. Return gnocchi to the upper rack of the oven and broil until the veggies and gnocchi are lightly browned and the cheese is melted and bubbling, about 3-5 minutes more. \nIf desired, top with torn basil leaves and freshly-grated Parmesan. Dig in!