Preheat your oven to 180°C (350°F). Gather an 8-inch round cake tin, a roasting tray, and all the ingredients.

In a medium saucepan, heat 200g of granulated sugar over medium-low heat until it melts into a deep amber color (8–10 minutes). Pour the caramel into the cake tin and let it cool.

Whisk together 6 egg yolks, 320g of condensed milk, 350ml of evaporated milk, 2 teaspoons of vanilla extract, and 1/8 teaspoon of salt in a large mixing bowl. Strain the mixture and pour over the cooled caramel.

In a separate bowl, whip 3 egg whites with 1/4 teaspoon of cream of tartar. Gradually add 60g of sugar until stiff peaks form (4–5 minutes).

Mix together 3 egg yolks with 60g of sugar, 40ml of vegetable oil, 50ml of cold water, and 1 tablespoon of ube extract. Sift in 100g of plain flour, 1/2 teaspoon of baking powder, and 1/8 teaspoon of salt. Mix until just combined.

Gently fold the whipped egg whites into the cake batter. Pour the batter over the flan mixture in the cake tin.

Place the cake tin in a roasting tray filled with boiling water, halfway up the sides. Transfer to the oven.

Bake for 55–60 minutes. Check doneness with a toothpick; it should come out clean.

Let the cake cool in the tin for about 15 minutes. Invert onto a serving plate and cool completely at room temperature. Refrigerate for at least 4 hours, preferably overnight.