• Preheat your oven to 375℉ (or 190℃) and grease a 9x9x2.5-inch square baking dish.
• Add olive oil, onion and garlic with a pinch of kosher salt to a deep sided skillet. Heat on medium-low, stir and cook 5 minutes or until softened.
• Increase the heat to medium-high and add in the ground meat or sausage. Use a wooden spatula or spoon to break up the sausage. Stir often until no longer pink and the meat is browned. Drain and discard any fat in the pan.
• Once the sausage or meat is browned and the fat removed from the pan, pour in the marinara. I added 1 (28-ounce) jar to a liquid measuring cup and added enough water until it reached 4 cups.

  Remove the pan from the heat and pour the marinara. There's no need to simmer.
• Meanwhile, in a medium bowl combine the ricotta, egg, 2 tablespoon parmesan cheese and parsley. Season with a pinch of kosher salt and some freshly ground black pepper. Stir to combine.
• Spread a few large spoonfuls of sauce on the bottom of the prepared baking dish.

LAYER ONE:

• Lay down 2 noodles, side by side and top with 1/3 (I just eyeball it) of the ricotta mixture and spread it evenly.
• Top with 1/4 of the sauce and sprinkle with a little less than 1/3 of the 2 cups of mozzarella (or about a generous 1/2 cup).

LAYER TWO:

• Lay down 2 noodles (going the opposite direction), side by side and top with 1/3 of the ricotta mixture and spread it evenly.
• Top with 1/4 of the sauce and sprinkle with a little less than 1/3 of the mozzarella.

LAYER THREE:

• Lay down 2 more noodles (going the opposite direction) side by side and top with the remaining 1/3 of ricotta mixture and spread it evenly.
• Top with 1/4 of the sauce. (no cheese)

LAYER FOUR:

• Lay down the final 2 noodles (going the opposite direction) side by side and top with the last of the sauce.
• Sprinkle with the remaining mozzarella cheese and parmesan.
• Transfer to a rimmed metal baking sheet (to catch any spill over) and bake uncovered for 30 to 40 minutes or until bubbly and the cheese is golden brown.
• Let cool 10 minutes before slicing and serving.