Position the racks in the top and bottom thirds of the oven; preheat to 350°. Bring a medium pot or kettle of water to a boil. Coat twelve 8-oz. ramekins or other small ovenproof dishes with the butter. Add 1 tbsp. cream and 1 tbsp. cheese to each dish and gently stir together. Crack 2 eggs into each dish and top with a pinch of sea salt and pepper.
Divide the ramekins between 2 large roasting pans. Add enough boiling water to come halfway up the sides of the ramekins. Carefully transfer to the oven and bake until the whites are just set and the cream is bubbling, 10 to 12 minutes.
Using tongs, carefully transfer the ramekins to a wire rack to cool slightly, 2 to 3 minutes. Top with the frisée, chives, and parsley. Serve with the crusty bread, if using.