Remove stems from brussels sprouts and slice in half lengthwise. Place sliced side down in skillet, add water, lemon zest, salt, and pepper, and cover. Cook on medium-high heat for about 6 minutes until water is completely absorbed.

Remove lid, add olive oil and lemon juice, and increase heat to high. Cook uncovered for about 3-5 minutes until bottoms are brown and slightly charred. Top with red pepper flakes (if desired) or shredded parmesan cheese and serve!