Preheat oven to 350°F (175°C).
Prepare caramel by heating sugar in a flan mold over low heat until melted and golden. Swirl to coat the bottom and let it cool.
In a large bowl, whisk eggs lightly. Add condensed milk, evaporated milk, coconut milk, and mix well.
Add grated cassava, ube halaya, sugar, vanilla, and salt. Mix until well combined.
Pour the mixture into the prepared caramel-lined mold.
Cover with aluminum foil and place the mold in a water bath (bain-marie).
Bake for 50-60 minutes or until a toothpick inserted comes out clean.
Let it cool completely. Refrigerate for at least 2 hours before unmolding.
To unmold, run a knife around the edges and invert onto a serving plate.