Preparation 1. Place 5 pudding cups in a deep baking dish. 2. Make the caramel sauce: Combine the sugar and cool water in a small pot over medium heat. Cook, swirling the pan around, until the mixture turns amber in color and smells toasted. Add the hot water, then remove the pan from the heat. 3. Divide the sauce between the pudding cups and refrigerate until set, 30 minutes. 4. Preheat the oven to 320˚F (160˚C). 5. Make the pudding: In a medium bowl, whisk together the sugar, eggs, and egg yolk. Gradually add the warm milk, whisking to combine. Strain through a fine-mesh sieve into a large liquid measuring cup. Set aside. 6. Make the castella batter: Set a large bowl over a medium pot of simmering water. Add the eggs, sugar, and honey to the bowl and whisk well. 7. Remove the bowl from the pot and beat with an electric hand mixer on high speed until the texture is fine for 3 minutes. Sift the flour into the bowl and fold with a rubber spatula to incorporate. 8. Divide the reserved pudding mixture between the pudding cups, then dollop the castella batter on top. 9. Pour hot water into the baking dish until it reaches the pudding mixture line. 10. Bake for 35 minutes, until the tops are golden brown. 11. Remove from the oven and let cool, then chill in the refrigerator for 2 hours before serving. 12. Enjoy!