You may have heard this dish called flan in Mexico, crème caramel in France, or flan de leche in Spain. However you name it, this comforting, classic dessert has velvety egg custard baked atop a layer of caramelized sugar that later forms its signature syrupy caramel sauce. But all too often flan's texture disappoints, with its creamy potential reduced to a rubbery let-down from overcooking. Or, it bakes into a pin-holed mess from bubbles in the custard mixture. When it comes to creating flan's coveted smooth, creamy texture, baking low and slow with a water bath is key.
Prepare the Oven & Pan
Preheat the oven to 325 degrees.
Generously grease the insides of six individual 6-ounce ramekins with butter. Line a roasting pan or 9×13-inch baking dish with a thin kitchen towel or a double layer of paper towels and place ramekins on top. The towel keeps the ramekins from sliding around in the baking dish once a water bath is added.
Caramelize the Sugar
Place 1 cup granulated sugar in an even layer in a slightly-warmed saucepan or deep skillet. Cook over medium-low heat until the sugar liquefies and turns a deep-copper color. Stir sparingly with a heat-proof spatula, as needed, to remove lumps. When done, caramelized sugar should read 340 to 350 degrees on a candy thermometer.
Stay close to the stove and keep a watchful eye on the sugar, as it can turn from granular to liquefied and burnt rather quickly. Caramelizing can take some time, but resist the urge to turn up the heat to speed up the process. Turning up the heat cooks the sugar too quickly and can create a burnt taste.
Pour Caramel into Ramekins
Spoon about 2 tablespoons hot caramel into each ramekin, tilting the ramekin immediately after adding the caramel to completely cover the bottom. Set aside.
Work quickly, as the caramel will harden rapidly once removed from the heat. If it hardens too much, gently reheat the caramel over low to medium-low heat until it liquefies again. Or, fill ramekins near the stove with the pot of caramel still over very, very low heat.
Make the Custard Mixture
In a large bowl, gently whisk 4 eggs until they are pale yellow. Add a 12-ounce can of evaporated milk, a 14-ounce can of sweetened condensed milk, and 2 teaspoons vanilla extract. Very gently whisk until well combined.
For a silky and smooth flan, you want to avoid creating bubbles when making the custard mixture. Bubbles in the mixture create holes in the baked custard, and lead to an unpleasant texture. When whisking, whisk very gently using more of a stirring motion than a whipping motion. Also, consider making the custard mixture while the sugar caramelizes so it can rest for a few minutes, releasing some of the air bubbles.
Carefully spoon or pour custard to fill each caramel-lined ramekin.
For the smoothest, silkiest texture, strain the custard mixture through a mesh sieve when filling ramekins to remove any bubbles and lumps.
Make a Water Bath
Place the baking dish with the filled ramekins in an oven preheated to 325 degrees. Create a water bath by carefully pouring hot tap water into the baking dish until it reaches halfway up the sides of the ramekins. The water bath ensures the temperature of the custard rises slowly and therefore thickens gradually, creating a creamy smooth texture.
Use very hot tap water, but not boiling water. Boiling water will cause the edges of the flan to cook too quickly and create a texture that’s too firm.
Bake & Chill
Bake for 45 minutes, until a knife inserted just to the side of the center comes out clean.
Immediately remove ramekins from the hot water bath. Let stand until cool enough to handle, then cover each with plastic wrap and chill at least 4 hours or overnight.
Over baking will create a rubbery texture that’s too firm. The custard is done when the edges are set but the center still jiggles. Once out of the oven, the custard will continue to cook a bit due to residual heat, so be sure to remove the flans from the oven while they still have some jiggle in them.
Carefully run a sharp, thin-bladed knife around the edge of each flan, taking care to stay to the edges and not cut into the custard.
Invert & Serve
Place a small serving plate upside-down on top of one ramekin. Holding the two together, invert so the ramekin is on top. Gently lift off the ramekin, allowing the flan to slip out onto the plate. Let the caramel sauce drip on top of the flan.
Repeat with remaining ramekins.
The longer the flans chill, the more caramel will become liquid. Prepare flans up to 2 days ahead to create more caramel sauce to for drizzling (and enjoying!) when ramekins are inverted.