Place yeast, sugar and warm milk in the bowl of a stand mixer with the paddle attachment attached and proof yeast 5-10 minutes.
Add egg, vanilla, honey, 2 1/2 cups flour, brown sugar, and salt to the yeast mixture and beat on low speed until combined.
Switch to the dough hook attachment. Add butter 4 tbsp at a time, kneading until totally incorporated.
Add the rest of the flour and knead 5-10 minutes.
Cover and let the yeast dough rise in a warm place covered in a light cloth until doubled in size, around 2 hours.
Knock the dough down and wrap in plastic wrap 2-3 times. Let the dough rest overnight in the refrigerator.
The next day, let the dough come to room temperature for about an hour. While the dough warms, put the sugar cubes in a small Ziploc bag. Bash with a rolling pin until the cubes turn into small pieces, no larger than 1/8 of an inch.
Knead the sugar into the Belgian waffle dough. Now you have liege waffle dough on your hands! Once mixed, divide the dough into 6 dough balls of equal size.
Cook in a waffle iron on medium heat (we used level 4 of 6 on our Waring waffle iron) for several minutes, or until a rich golden brown in color.