Boil water in a large pot and add the pasta. Cook according to package instructions until al dente, about 8-10 minutes. Reserve 1 cup of pasta water before draining.

In a large skillet, heat olive oil over medium heat. Add the diced onion and sauté until it becomes translucent and soft, about 5 minutes.

Stir in the minced garlic and cook until fragrant for about 30 seconds. Pour in the canned diced tomatoes with their juices, and let it simmer for 5 minutes.

Mix in the heavy cream, reduce the heat to low, and let the sauce simmer until it thickens slightly, around 5 minutes.

Add the shrimp, seasoning generously with salt, pepper, and chopped basil. Cook until the shrimp turn pink and opaque, about 3-4 minutes.

Toss the cooked pasta into the skillet, mixing well with the sauce. Use the reserved pasta water to reach the desired sauce consistency.