Mix Egg, sugar, emilsifier, vanilla and salt till soft and fluffy, add in strained flour, cornstarch and milk powder, stir well.
Insert melted butter, ube and purple food coloring, bleanded well using spatula.
Pour batter into 20 x 20 cm grease baking sheet and lined with bake paper, bake about 15-20 minutes in 180C egree or till done.
When perfectly cook, enter from the pan and cooling down, filling with butter cream and spread greated cheese.
Slowly and gentle roll the cake and topping it again with rest butter cream and garnish with greated cheese. Ready to be serve.