In a pan on medium heat, toast walnuts for about 5 minutes, stirring constantly. Remove and let cool. Once cooled, crush with the flat of a knife or a rolling pin. Set aside.
Cut avocados in half, then deseed and scoop out flesh. Set aside.
In a pot on medium heat, melt gula melaka, stirring constantly. When fully melted into a syrup, set aside to cool.
In a blender, add avocado, ice, milk, and 4 tbsp melted gula melaka. Blend for 2 minutes, or until desired consistency.
Pour into a tall glass and top with crushed walnuts.