Fill a large pot with water, add 1 tablespoon kosher salt, and bring it to a boil over high heat.

While the water heats, grate the Parmesan cheese. Set aside 1/4 cup for serving and keep the remaining 1/2 cup for the sauce.

When the water reaches a full boil, add the penne to the pot and stir well so it does not stick together.

Cook the penne until tender with a little bite left in the center, 10 to 12 minutes. Stir once or twice while it cooks.

While the pasta cooks, put the cottage cheese into a blender.

Add the sun-dried tomatoes, chopped garlic, lemon zest, lemon juice, and 1/2 cup of the grated Parmesan to the blender.

Ladle 1/2 cup of the hot pasta cooking water into the blender.

Blend until the sauce is very smooth, about 30 seconds. If it looks too thick to pour, add 2 to 3 more tablespoons of pasta water and blend again.

About 2 minutes before the pasta is done, set a large skillet over low heat and add the olive oil.

Pour the blended sauce into the skillet and warm it gently for 1 minute, stirring often. Keep the heat low so the sauce does not boil hard.

Add the spinach to the skillet a handful at a time. Stir after each handful until the leaves wilt into the sauce.

Scoop out another 1/2 cup of pasta cooking water and set it next to the skillet.