Heat oven to 350 degrees F (177 degrees C). Spray a 3-quart baking dish with non-stick cooking spray or lightly grease with butter. (A 13-inch by 9-inch pan works well for this).
1- Bring a large pot of salted water to a boil then add pasta and cook according to the package directions (this usually takes about 10 minutes). Before draining, reserve about a 1/4 cup of the pasta water – we will use this later. Then, drain pasta.
2- While the pasta cooks, heat the tomato sauce. You can do this on the stove or in the microwave, and then set aside.
3-In a small bowl, stir the basil pesto and sour cream together, and then set aside.
4- Add drained pasta to a large bowl then add spinach, drained artichokes, hot tomato sauce and about a 1/4 cup of the reserved pasta water. Then, toss.
5-Add about half of the pasta and spinach mixture to the baking dish. Then, spread the sour cream and pesto on top. Scatter about half of the shredded mozzarella cheese on top of the sour cream then add the rest of the pasta on top of that. Press everything down into the baking dish then scatter the rest of the mozzarella cheese on top.
6- Place the baking dish onto an aluminum-lined baking sheet (just in case any sauce drips over the sides of the baking dish). Then, bake for about 30 minutes or until cheese has melted and the sauce is bubbling.
Let the baked ziti cool for 5 to 10 minutes before serving – it’s really hot! Then, enjoy!