For the pasta, bring a large pot of salted water to a boil over high heat.
Meanwhile, heat oil in a large Dutch oven over medium-high heat. Add the sausage and cook until browned, about 5 minutes. Season with salt and pepper.
Reduce the heat to medium, add the garlic and red pepper flakes and cook, stirring occasionally, until fragrant, about 1 minute. Add the wine and cook until evaporated, about 1 minute. Stir in the mustard and cream and bring to a simmer.
Cook the pasta according to package instructions. Using a slotted spoon, transfer the pasta to the pot with the sauce. Add 1/2 cup of the pasta cooking water and the Parmesan and stir constantly until the noodles are coated with a light, glossy sauce, about 3 minutes. Stir in the basil. Add salt and pepper to taste.
To serve, top each serving with a dollop of ricotta, garnish with basil leaves and sprinkle with Parmesan. Serve immediately.