Bring a large pot of salted water to a boil.

Add the spaghetti and cook according to package instructions until al dente.

While the pasta is cooking, heat oil and butter in a separate pan over medium heat.

Add the chopped onion and garlic to the pan and sauté for 2 minutes, or until softened.

Drain the artichoke hearts, squeeze out excess water, and add them to the pan.

Add the canned tomatoes, salt, and pepper to the pan and simmer for 8-10 minutes.

Reserve about 1/4 cup of the pasta water before draining the spaghetti.

Drain the spaghetti and toss it with a little olive oil to prevent sticking.

Reduce the heat under the artichoke sauce to low.

Stir in the sour cream and chicken stock (or stock cube dissolved in water). Add pasta water if the sauce is too thick.

Combine well and simmer for a couple of minutes.

Add the cooked spaghetti to the sauce and toss to coat.

Stir in most of the Parmesan cheese, reserving some for garnish.

Serve immediately, garnished with the remaining Parmesan cheese and chopped chives.