Prepare the caramel: In a heavy-bottomed saucepan, combine 1 cup of granulated sugar and 1/4 cup of water. Heat over medium-high heat without stirring until the sugar dissolves and turns into a deep amber caramel. Do not burn.

Coat the mold: Carefully pour the hot caramel into a 9-inch round baking dish or a bundt pan, tilting the pan to coat the bottom and sides evenly. Set aside to cool and harden.

Preheat oven & water bath: Preheat your oven to 350°F (175°C). Place the caramel-coated pan inside a larger baking pan (roasting pan) that can hold hot water.

Prepare the custard: In a large bowl, whisk together the eggs until well combined. Gradually whisk in the sweetened condensed milk, evaporated milk, whole milk, vanilla extract, and a pinch of salt until smooth. Do not overmix, as too much air can cause bubbles.

Pour and bake: Carefully pour the custard mixture through a fine-mesh sieve into the caramel-lined pan. This step ensures a silky smooth texture by removing any eggy bits or air bubbles.

Bake in water bath: Pour hot water into the larger baking pan, around the flan mold, until it reaches about halfway up the sides of the flan mold.

Bake: Bake for 50-60 minutes, or until the edges are set but the center still jiggles slightly when gently shaken.

Cool and chill: Carefully remove the flan pan from the water bath. Let it cool completely on a wire rack at room temperature. Once cool, cover with plastic wrap and refrigerate for at least 4 hours, preferably overnight, to allow it to set fully and for the flavors to meld.

Unmold and serve: To unmold, run a thin knife around the edge of the flan. Place a serving plate upside down over the flan pan, then quickly and carefully invert the pan onto the plate. The caramel will drizzle over the flan. Serve chilled.