Slicing the Brussels sprouts can be a bit laborious; if you have a food processor with a slicing blade, this would be a good way to make use of it. Brussels sprouts can go from crisp and nutty to soggy and bitter if they are overcooked, so cook them quickly in a large sauté pan so they still retain their crunch and vibrant green! Cut the sprouts in half lengthwise. Then thinly slice the sprouts crosswise. As you slice the sprouts, put the slices into the bowl with the lemon juice. Toss them to separate the leaves and coat with a little of the lemon juice. Sauté them until the shaved sprouts are just lightly wilted and cooked, but still green and firm, about 3 to 4 minutes. Remove from heat and sprinkle with lemon zest. Add more salt and pepper to taste. Serve immediately.