Prepare the Caramel – In a saucepan over medium heat, melt the sugar until it turns golden brown. Quickly pour the caramel into a round baking dish, tilting to coat the bottom evenly. Set aside to cool.
Make the Custard – In a mixing bowl, whisk together sweetened condensed milk, coconut milk, whole milk, eggs, egg yolks, vanilla extract, and salt until smooth.
Strain the Mixture – Pour the mixture through a fine-mesh sieve to remove any egg solids, ensuring a silky texture.
Bake the Flan – Pour the custard over the cooled caramel in the baking dish. Place the dish in a larger roasting pan and fill the pan with hot water halfway up the sides (water bath method).
Cook & Cool – Bake at 350°F (175°C) for 50-60 minutes, or until the center is set but slightly jiggly. Remove from the oven and let it cool at room temperature before refrigerating for at least 4 hours.
Unmold & Serve – Run a knife around the edges of the flan and invert onto a plate to release the caramel topping. Garnish with toasted coconut flakes and serve chilled.