Preheat oven to 425 F. Brown and drain ground beef in a pan over medium heat. Add onion, garlic, oregano, salt and pepper. Cook on low until onions become opaque.
While ground beef is cooking, boil water in a separate pot, adding half a box of jumbo shells; cook until al dente and strain. Place noodles back into the pot and stir in about 1/2 cup of marinara sauce to prevent sticking.
In a bowl, mix ricotta, 1 cup grated mozzarella, 2 eggs and freshly chopped basil. Stir in ground beef mixture until evenly mixed.
Pour about 1 cup of marinara into a 13 x 9 baking dish. Spoon in lasagna filling until shell is stuff (about 2 big spoonfuls) place in baking dish and repeat until baking dish is full. Top with remaining grated cheese and more marinara if desired.
Cover baking dish with tin foil and bake for 40 minutes. Remove tin foil and bake for another 5 minutes. Enjoy!