Steps
1. Preheat oven to 300 degrees Fahrenheit.
2. In a small bowl, whisk together heavy cream and vanilla extract.
3. In a separate bowl, stir together sugar and egg until blended.
4. Gradually add cream mixture to egg mixture, whisking constantly.
5. Pour cream mixture into a ramekin. Place ramekin in a baking dish big enough to fit it.
6. Fill baking dish with warm water, reaching halfway up the ramekin.
7. Bake in preheated oven for 35 minutes.
8. Remove ramekin from baking dish and discard water.
9. Sprinkle raw sugar over the top of the custard, followed by lemon zest.
10. Using a small kitchen torch, melt the raw sugar until it forms a crust.
11. Garnish with additional lemon zest and serve.