Melt the white chocolate chips and unsalted butter in a microwave-safe bowl or saucepan over low heat, stirring continuously until smooth, about 2-3 minutes in the microwave or 5-7 minutes on the stovetop.

Whisk together the eggs and granulated sugar in a medium mixing bowl until thick, pale, and frothy, about 4-5 minutes.

Slowly whisk the cooled chocolate-butter mixture into the egg-sugar mixture, then gently fold in the ube halaya and ube extract.

Sift together the all-purpose flour and salt, then gently fold into the wet ingredients until no dry flour remains.

Preheat the oven to 425°F (218°C) and grease ramekins with non-stick spray or butter. Fill each ramekin about 3/4 full with batter.

Bake the ramekins for 11-12 minutes, until the edges are set but the centers remain jiggly.

Let the cakes cool in ramekins for 1-2 minutes, then invert onto plates and serve immediately with vanilla ice cream.