Make the caramel

• Melt the sugar in a saucepan over medium heat without stirring until it turns a deep amber.
• Pour the caramel into the baking dish and swirl to coat the bottom evenly.

Prepare the custard

• Whisk the eggs with the sugar and a pinch of salt until smooth, without making foam.
• Stir in the condensed milk, evaporated milk, whole milk and vanilla.
• Strain the mixture through a sieve to remove any foam or lumps.

Bake in a water bath

• Pour the custard over the set caramel in the dish.
• Place the dish in a larger pan and fill with hot water halfway up.
• Bake at 160 °C until the flan is just set with a slight wobble in the center.

Chill and unmold

• Let the flan cool, then refrigerate until completely cold.
• Run a knife around the edge and invert onto a plate to release the caramel.