Heat the butter in a large, deep skillet over medium-high heat, for about 2 minutes.
Add the garlic and cook it for 30 seconds.
Add the kale in batches, as shown in the video below.
Stir-fry until the kale is tender and slightly wilted, about 5 minutes.
Stir in the salt, black pepper, and lemon juice.
Serve immediately.
Video
Notes
Make sure to avoid overcooking the kale. You want it to still have some "bite," just like al-dente pasta. You don't want it mushy and limp.You can keep the leftovers in the fridge, in a sealed container, for 3-4 days. They keep pretty well, although they won't be as good as when freshly made. Reheat the leftovers gently, covered, in the microwave at 50% power.