Yield: 6 servings
1/2 cup sugar
2 tablespoons water
2 large eggs
3 large egg yolks
1/4 teaspoon grated zest from 1 lemon
1 (14-ounce) can sweetened condensed milk
1 1/2 cups low-fat milk
Adjust oven rack to middle position and preheat oven to 350 degrees.
Bring sugar and water to boil in small saucepan, swirling pan gently, until sugar has dissolved, about 3 minutes. Reduce to simmer and cook, gently swirling pan occasionally, until mixture has caramelized to a deep, dark mahogany color, 7-10 minutes. Carefully pour caramel into 9-inch cake pan and cool slightly until hardened.
Place pan in center of large roasting pan. Bring a kettle or large saucepan of water to boil over high heat.
Meanwhile, whisk whole eggs and egg yolks together in medium bowl until thoroughly combined, about 1 minute. Whisk in zest and milks. Pour mixture into cake pan and gently place roasting pan on oven rack. Being careful not to splash any water inside pan of custard, pour boiling water into roasting pan until water reaches halfway up side of cake pan.
Bake until center of custard is just barely set, no longer sloshy, and an instant-read thermometer registers 170-175 degrees, 30-40 minutes (start checking temperature after 25 minutes).
Carefully remove roasting pan from oven and carefully transfer cake pan to wire rack. Let cool to room temperature, about 2 hours. Wrap cake pan with plastic wrap and refrigerate custard until completely chilled, at least 2 hours and up to 24 hours.
Run a knife around cake pan to loosen custard. Invert large serving platter over top of cake pan. Grasping both the cake pan and platter, gently flip custard onto platter, drizzling any extra caramel sauce over top (some caramel will remain stuck in pan). Serve immediately.
Source: "The Best International Recipes: A Home Cook's Guide to the Best Recipes in the World," Cook's Illustrated magazine