Preheat the oven to 325°F (160°C). Lightly grease four ramekins with butter or oil.
In a mixing bowl, whisk together the crabmeat, Parmesan cheese, heavy cream, salt, cayenne pepper, lemon zest, and egg yolks until well combined.
Divide the mixture evenly into the ramekins.
Place the ramekins in a baking dish and fill the dish with hot water until it reaches halfway up the sides of the ramekins.
Bake for 25-30 minutes or until the custard is set around the edges but slightly wobbly in the center.
Let the ramekins cool for 10 minutes. Sprinkle a thin, even layer of granulated sugar on top of each.
Caramelize the sugar using a kitchen torch or place the ramekins under a broiler for a few minutes until golden brown.
Serve warm or at room temperature.
Notes
For variations, add fresh herbs like dill or parsley, or a dash of hot sauce for extra heat. Serve with crusty bread or a side salad for a complete dish.