Sauté the base: Heat olive oil in a large skillet over medium heat. Add the onion and cook until soft and golden, about 5 minutes. Stir in garlic and cook for another minute.
Deglaze with wine: Pour in the white wine and let it simmer for 2–3 minutes until it reduces slightly. This step deepens the flavor of the sauce.
Build the sauce: Stir in Dijon mustard, Italian seasoning, and crushed tomatoes. Let it simmer for 5–6 minutes so the flavors come together.
Make it creamy: Reduce the heat and pour in the heavy cream. Stir until the sauce is smooth and velvety. Season with salt and black pepper.
Cook the gnocchi: In a separate pot, bring salted water to a boil. Cook the gnocchi according to package instructions (usually 2–3 minutes). Drain and add straight into the sauce.
Toss and finish: Stir the gnocchi into the sauce until every piece is coated. Add fresh basil on top before serving.
