In your stand mixer bowl, combine warm milk, active dry yeast, and brown sugar. Let it rest for 10 minutes to activate the yeast.
Add flour, egg, salt, and vanilla. Knead with the dough hook attachment for 3 minutes until a dough forms.
Incorporate softened butter and knead on medium-high speed for about 5 minutes until you have a soft, stretchy dough.
Transfer the dough to a clean bowl, cover with plastic wrap, and let it rise in a warm place until it doubles in size (about 60 minutes).
Once risen, flatten the dough on a floured surface. Sprinkle half of the pearl sugar, press in, and roll up the dough. Repeat with the remaining sugar. Stretch and knead to fully incorporate the pearl sugar.
Preheat the waffle maker for about 10 minutes.
Divide the dough into 4 equal parts.
Working one piece at a time, cook the waffles until golden and cooked through. The exact time may vary, but around 6-7 minutes on medium heat worked for me.
Serve with Nutella and fresh berries (or enjoy them on their own)!