Cajeta Flan

Directions

1. 1
   Bring sugar and water to a boil in a small heavy saucepan over medium heat, stirring until sugar has dissolved, then wash down any sugar crystals from side of pan with a pastry brush dipped in cold water. Boil, without stirring, swirling pan occasionally so caramel colors evenly, until dark amber.
2. 2
   Immediately divide caramel among ramekins and swirl each ramekin to coat bottom and about halfway up side.
3. 3
   Preheat oven to 350°F with rack in middle.
4. 4
   Put cajeta, half-and-half, and lime zest in a heavy medium saucepan. Split vanilla bean lengthwise and scrape seeds into saucepan, then drop in pod. Bring to a simmer, stirring until smooth.
5. 5
   Whisk together whole eggs and yolks in a large bowl. Slowly whisk in hot liquid, then strain through a fine-mesh sieve into another bowl. Ladle custard into ramekins.
6. 6
   Bake in a hot water bath until edge is set but a quarter-size spot in center is still wobbly, 30 to 40 minutes.
7. 7
   Remove ramekins from water and cool at least 30 minutes (custard will continue to set). Unmold just before serving. Serve warm or at room temperature.