Heat a pan on medium heat to melt butter.
Add salted egg yolk to cook until bubbly.
(Salted egg yolk was steamed for 15-20 minutes then mashed)
Add fish sauce and sugar. Give it a quick mix.
Pour in evaporated milk, bring to boil, and remove from heat immediately.
Pour into the blender to blend until thick and smooth.
Garnish platter & serve with dipping sauce.