Warm oil in a large (10-inch) skillet over medium high-heat, add beef and sprinkle with ½ tsp salt, ½ tsp pepper and red pepper flakes. Cook beef until cooked though, stirring occasionally. Drain if necessary.

Meanwhile in a medium bowl combine ricotta cheese, ½ cup Parmesan cheese, ½ cup shredded cheese, egg and ½ tsp salt and ½ tsp pepper. Mix until well blended.

Fill a 1 gallon resealable bag with ricotta mixture. Clip off the tip of the bag (so it is still small enough to fit inside manicotti shell). Stick a clean finger about 1” into one end of the shell and place end of bag into the other end of the manicotti shell and squeeze mixture into shell until no more will fit. Turn shell over and fill the remaining portion. Repeat until all shells are filled.

Add tomatoes, sauce, paste, Italian seasoning and water. Turn heat to high. Place stuffed manicotti into sauce. Press down to get them under the sauce mixture. Spoon sauce over shells. Cover skillet to bring to a boil, reduce to simmer (sauce should still be bubbling). Cook covered until pasta is al dente, about 10 minutes.

Sprinkle remaining cheese over top of skillet, allow cheese to melt. Sprinkle with fresh parsley if desired.

Serve and enjoy!