Wash and dry spinach. We wash it and spin it in our salad spinner. *If using frozen spinach, put it into a strainer and put it under warm water to thaw and squeeze out extra water).
Smash the garlic and peel it.
In a large skillet over medium heat, add the oil until it shimmers, about 1-2 minutes. Add the smashed garlic cloves to flavor the oil. Cook until just fragrant (don’t let it brown). Remove the garlic and throw it away.
Add half of the spinach and cook allowing it to wilt and turning it with tongs. Once it starts to wilt, after about a minute, add the remaining spinach. Sprinkle it with salt and pepper and cook until wilted.
Add the lemon juice on top. (lemon juice unlocks the iron in the spinach!)