Preheat oven to 350 degrees and grease a 10x12 (2 qt) baking dish (slightly smaller than a 9x13, but 9x13 would work)
Bring a large pot of salted water to a boil. Cook jumbo shells according to package instructions to "al dente". Drain pasta when cooking is complete, and drizzle with olive oil to avoid sticking together, set aside.
In a medium bowl combine ricotta cheese, 1/4 cup of the Parmesan cheese, Italian seasoning, parsley, and garlic powder. Stir until well combined.
Spoon out just enough sauce (sauce only, no meatballs) to cover the bottom of the baking dish. Scoop about 1 tbsp of ricotta cheese into each cooked shell. Then place 1 meatball into each of the cooked shells. Arrange into the baking dish. Pour remaining sauce over the shells. Sprinkle shredded mozzarella and remaining 1/4 cup of parm over the top. Cover with foil and bake for 30-40 minutes.
No freezer meatballs on hand? Make some! Recipe link is in the original post. BUT, you can sub ground beef, turkey, or Italian sausage and brown that up to mix in with the sauce. Also would be great as a meatless dish!
Like it spicy? Add some red pepper flakes!