01 -
Warm your oven to 350°F. Lightly coat a square 8-inch dish or any 2-quart baking container with olive oil.
02 -
Thaw the spinach in your microwave following package instructions. Squeeze out all water by putting the thawed spinach in a strainer and pushing down many times with a big spoon until it's dry. Put aside.
03 -
Put the olive oil in a big pan over medium-high heat for about 3 minutes. Throw in the beef, onion, and ½ teaspoon kosher salt. Stir with a wooden spoon, breaking the beef into little bits, until onions get soft and meat turns brown, around 5-7 minutes.
04 -
Pour off extra fat from the beef mix and put it back in the pan. Add the garlic and stir for 30 seconds, then mix in the tomato sauce. Turn off the stove.
05 -
Warm the cream cheese in a medium bowl for 40 seconds to soften it. Stir with a fork until it's smooth. Mix in the egg, black pepper, and the other ½ teaspoon of kosher salt. Keep mixing until totally smooth. Add the dried spinach and blend everything together well.
06 -
Smooth the spinach mix across the bottom of your oiled dish. Cover with the meat mix, then sprinkle mozzarella over the top.
07 -
Pop it in the oven until the cheese gets bubbly and slightly golden, about 30 minutes.
08 -
Let it sit for ten minutes before you cut and serve it.