Heat olive oil in a large sauté pan set over medium-high heat until it shimmers.
Add garlic, and cook until soft.
Add kale to the pan, turn the heat to high and add the stock
Use a spoon to toss the greens in the oil and stock, then cover and cook for approximately 3 – 5 minutes, until it is soft and wilted, but still very green.
Remove cover and continue to cook, stirring occasionally until all the liquid has evaporated, another 1 to 2 minutes.
Season to taste with salt and peppers, add vinegar and toss to combine.