Preheat oven to 350 degrees. Spread 1/2 cup of pasta sauce on bottom of an 8x13 baking dish, and set aside.
Cook manicotti according to package directions and drain.
While pasta is cooking, combine ricotta, egg, spinach, parmesan, seasonings, and cooked ground beef. Stir to combine well.
Spoon ricotta and beef mixture into plastic zip bag. Twist to tighten the bag and snip the corner off. Try to make the bag opening slightly smaller than the manicotti opening.
Working slowly, squeeze the bag and stuff the manicotti shells one end at a time. Place stuffed shells in the baking pan. Top with the remaining 2 1/2 cups of pasta sauce. Cover with shredded mozzarella.
Bake for 30 minutes, remove and serve hot.