Add milk in a bowl. Combine together the baking soda and vinegar and combine with the milk.
Whisk the egg in a bowl, add the melted butter to the egg and mix. (Butter should not be hot, just very warm)
Pour the butter mixture to the milk and mix.
Add in the sifted flour and mix until well incorporated. The dough will be hard and flakey.
Shape the dough into three large balls. Add to a parchment paper-lined plate and add the dough balls, freeze for at least an hour or overnight.
Preheat the oven at 355°F and line two baking sheets with parchment paper. Grate the frozen dough. Spread the grated dough evenly among the baking sheets.
Bake for 30-35 minutes. After about 15 minutes of baking, mix the flakes to ensure even baking. Bake another 10 minutes and mix again.
Finished flakes will have a nice golden color to them. Don’t overcook or else the flakes will burn in some areas. Let flakes cool completely before adding cream to them.
Blend the walnuts and add to cooled flakes and mix.
Cream the butter and add in the condensed milk and combine. Beat the butter, add to the condensed milk and beat again. Add to the flakes/walnuts and mix with a spatula.
In a bowl, add the dough flake mixture and the cream and mix until well combined.
Form 24 balls out of the mixture. For easier assembly work with damp hands.
Refrigerate for at least an hour. Dust tops of balls with powdered sugar before serving.