First, prepare the pasta shells according to package directions for AL DENTE. You want to slightly undercook the shells so they won’t be too soft after baking. Drain and set aside.
Preheat oven to 350 degrees Fahrenheit. Spoon about 1/2 cup of the marinara sauce into the bottom of a lightly greased 8×10 baking dish. Set aside.
In a large bowl, stir together the ricotta cheese, 1/2 cup of parmesan cheese, sour cream, salt, pepper, and all seasonings. Combine until smooth. TASTE it and re-season to your preference. Then add the egg.
Gently fold in the fresh chopped spinach and basil until well incorporated.
Next, transfer the ricotta filling to a piping bag (or ziplock bag). Snip off of the end and fill each shell with the mixture.
Place each shell into the baking dish on top of the marinara. Repeat until all shells have been filled.
Spoon the remaining sauce over the top of the shells and top with mozzarella cheese. Sprinkle with parmesan.
Cover and bake for 30 minutes. You can remove the foil during the last 5 minutes of baking if desired to melt the cheese until bubbly.