In a small bowl combine yeast, water, sugar and salt and let rest for 15 minutes. In the bowl of a stand mixer fitted with the paddle attachment, place the flour and make a well in the center. Pour the yeast mixture into the well and mix on medium speed until well blended. One at a time, add the eggs, then the butter a little bit at a time, and the vanilla, mixing well after each addition. The batter will be thick and very sticky.
Remove the bowl from the mixer, cover with plastic wrap, and let rise in a warm place until doubled in volume, about 1 hour. Gently fold in the pearl sugar and let the dough rest for another 15 minutes.
While the dough is resting, preheat your waffle iron. Scoop a 2 inch ball of dough onto the center of each section in the iron. Bake 3-5 minutes or until golden brown and crunchy.