Remove the spinach stems. Tear the leaves into large pieces. Fill a large bowl with cold water and wash the spinach. Repeat 2 or 3 times until the spinach is thoroughly cleaned. Drain.

In a large skillet, heat half the oil over medium heat, add the garlic and stir until it begins to turn golden, about 3 minutes. Remove the garlic and discard. Add the spinach in batches, stirring to wilt, before adding more. When all the spinach has been added, raise the heat to high, season with salt and pepper, and cook, covered, for 3 minutes. Drain the spinach in a colander. Return spinach to the skillet to heat through. Serve in a medium bowl, drizzled with the remaining oil and garnished with lemon wedges, if desired.