Heat the olive oil in a large skillet over medium-high heat. Add the gnocchi in a single layer and cook undisturbed for 3-4 minutes until golden brown. Flip and cook the other side for 3-4 minutes. Remove and set aside.
In the same skillet, reduce heat to medium. Add diced onion and sauté until soft and translucent, about 3-5 minutes. Add minced garlic and cook for 1 minute until fragrant.
Pour in the undrained diced tomatoes and stir. Let simmer for 5-7 minutes to meld flavors and reduce slightly.
Reduce heat to low. Slowly stir in the heavy cream and chopped basil leaves, reserving some basil for garnish. Season with salt and pepper. Warm through for 2-3 minutes, stirring occasionally.
Return the pan-fried gnocchi to the skillet and gently toss to coat evenly with the sauce. Cook together for 1-2 minutes until heated through.
Serve immediately with freshly grated Parmesan cheese and reserved basil leaves. Enjoy with a green salad or garlic bread for a complete meal.
