Heat a large skillet over medium heat. Add the butter, followed by the sliced garlic. Sauté for about 30 seconds until the garlic is fragrant but not browned.

Add the spinach to the skillet and sprinkle with a pinch of salt. Toss gently with tongs to coat the leaves, and cook for 2 to 3 minutes until the spinach is just wilted.

Remove the skillet from heat. Season with freshly ground black pepper. If desired, squeeze a lemon wedge over the top for extra brightness and sprinkle on some red pepper flakes. Serve immediately.