Simple and Creamy Spanish Flan

Step 1
Preheat the oven to 325 degrees F (165 degrees C). Place a 9-inch metal pie dish into a deep baking pan; pour boiling water into the baking pan to reach about halfway up the sides of the pie dish to make a water bath.

Step 2
Pour 1/2 cup sugar and 1 teaspoon water into a heavy saucepan over medium heat. Gently swirl mixture in the pan until sugar dissolves, melts, and turns into a golden-brown caramel syrup, about 10 minutes. Watch carefully, as sugar burns easily. Pour melted caramel into the warmed pie dish; gently tilt the dish to coat the bottom with caramel.

Step 3
Whisk egg yolks, condensed milk, evaporated milk, remaining 1/4 cup sugar, and vanilla in a bowl until creamy and thoroughly combined. If mixture is foamy, skim foam off with a folded paper towel. Gently pour custard over caramel in the pie dish. Cover the baking pan with aluminum foil.

Step 4
Bake in the preheated oven until custard is set but jiggles slightly when nudged, 45 minutes to 1 hour. Remove foil and place flan with the water bath in the refrigerator until chilled, about 2 hours.

Step 5
Remove the pie dish from the water bath; run a knife around the edges of flan. Invert flan onto a rimmed serving platter to release custard; let caramel sauce flow over flan.