Mix half the warm milk with the yeast and a pinch of sugar, and let sit in a warm place for 10-15 minutes to activate.

With a mixer, whip the egg, 1 tbsp sugar, salt, and the remaining milk for a couple of minutes. Add the activated yeast mixture and whip again.

Add the softened butter and flour with vanillin, switch to the dough hook attachment, and knead the dough. Cover with plastic wrap and let sit in a warm place for 30 minutes.

Crush the refined sugar with a rolling pin into small chunks, but not to a fine powder.

Heat the waffle iron, brushing it with vegetable oil. Scoop up a spoonful of dough, roll it in the crushed sugar, and shape it into a ball with your hands.

Place the ball on the waffle iron, close it, and cook until you get a big, puffy waffle with a crispy caramelized crust.