Vegetarian Stuffed Pasta Shells

This is not my own recipe.  It's from my friend Kristina, who says it's from the back of the box of pasta shells.  So I bought the pasta shells, followed the recipe (more or less), and used some of my friends suggestions as well.  Hope it turns out just as good as hers!

VEGETARIAN STUFFED PASTA SHELLS
1 box large pasta shells
1 onion, diced
1 tbsp. Tomato & Parmesan Cheese Ball Mix
2 big handfuls of baby spinach, chopped
500 g. cottage cheese
1 egg
1/3 c. grated cheese (it called for Parmesan, but I used Pecorino Romano because that's what was in the fridge.  Mozzarella would probably work too.)
1 jar pasta sauce (I used Tomato Basil flavour.)

Bring a large pot of water to a boil.  Add salt and some oil.  Cook the pasta shells for 10 minutes, stirring often to make sure they don't stick to the bottom.  While they are cooking, sauté the onions in some butter and olive oil until they are soft.  Add the seasoning (you can use whatever herbs you like - I chose the Epicure cheeseball mix because it's awesome in Italian-inspired dishes.)  Add spinach and let it wilt slightly, then remove from heat and let it cool a bit.  Add cottage cheese, egg, and grated cheese.  Drain pasta and run cold water over it so you can handle the shells easily.  Pour half the pasta sauce into a 9x13" baking dish, fill the shells with the spinach mixture, and lay them in the baking dish.  Cover with the remaining pasta sauce and cover with tinfoil. Bake at 350 F for 30 minutes.