Sprinkle the yeast and white sugar over warm milk in a small bowl. The milk should be no more than 100 degrees F (40 degrees C). Let stand for 15 minutes until the yeast softens and begins to form a creamy foam.
Whisk the eggs, melted butter, and vanilla extract into the yeast mixture until evenly blended; set aside. Stir together the flour and salt in a separate large bowl, and make a well in the center. Pour the egg mixture into the well, then stir in the flour mixture until a soft dough forms. Cover with a light cloth and let rise in a warm place (80 to 95 degrees F (27 to 35 degrees C)) until doubled in volume, about 30 minutes. Gently mix in the pearl sugar.
Preheat a waffle iron according to manufacturer's instructions.
Place a baseball-size ball of dough on the preheated waffle iron. Cook waffles until golden and crisp, about 2 minutes. Repeat with remaining dough. Allow waffles to cool for 2 to 3 minutes before serving.
