In a large skillet, heat a drizzle of olive oil over medium heat. Add the onions and sauté until translucent, about 3-4 minutes.
Add the garlic and cook for another minute until fragrant.
Add the Italian sausage to the skillet. Cook, breaking it up with a spoon, until browned and fully cooked, about 5-7 minutes.
Stir in the diced tomatoes along with their juices and the dried oregano. Bring to a simmer and let cook for 5 minutes to meld the flavors.
Add the chopped kale (or spinach) and let it wilt for about 2 minutes.
Reduce the heat to low and stir in the heavy cream, mixing well to combine. Allow it to heat through for another 2-3 minutes.
Meanwhile, cook the potato gnocchi in boiling salted water according to package instructions (usually about 2-3 minutes or until they float). Drain well.
Add the cooked gnocchi to the sausage and tomato mixture, gently tossing to coat the gnocchi in the sauce. Season with salt and pepper to taste.
Remove from heat and serve immediately, garnished with fresh basil and sprinkled with grated Parmesan cheese.
Notes
Feel free to substitute kale with spinach if preferred.