How to make it

1. Bake the potatoes. Heat the oven to 400°F. Scrub the potatoes clean and poke each one a few times with a fork. Rub them with a little butter or oil and sprinkle with salt. Put them right on the oven rack and bake for about 1 hour, until the skin is crisp and a fork slides in easily.
2. Boil the spaghetti. While the potatoes bake, bring a big pot of salted water to a rolling boil. Add the spaghetti and cook for the time on the box, usually 9–11 minutes, until tender but not mushy. Scoop out a cup of the pasta water, then drain.
3. Warm the sauce. Pour the marinara into a saucepan over medium heat and warm it for about 5 minutes, stirring now and then, until it is steaming.
4. Toss it together. Put the drained spaghetti back in the pot. Pour in the warm marinara, add 2 tablespoons of butter, the garlic powder and a splash of the pasta water. Toss until every strand is coated and glossy.
5. Serve it up. Split each baked potato open, fluff the insides with a fork, and top with butter, salt, pepper and sour cream if you like. Plate the spaghetti next to it with parmesan on top.