In the bowl of a stand mixer, whisk together warm milk, yeast, and sugar. Let mixture sit for 5-7 minutes until foamy and aromatic.
Add eggs, vanilla, and brown sugar to mixing bowl. Whisk until incorporated. Attach dough hook to stand mixer.
In a large bowl, whisk together flour, cinnamon, and salt. Add flour mixture in three additions. Mix on low speed until dough is a shaggy mess, about 2 minutes. Scrape down sides of bowl.
With the mixer running on low speed, add softened butter one tablespoon at a time. Once all the butter as been added, increase to medium speed. Knead for 5-7 minutes until dough is smooth and pulls away from the sides of the mixing bowl.*
Cover bowl and let dough rest for 2 hours at room temperature.
Punch down risen dough. Add pearl sugar. Use dough hook to mix in pearl sugar for 30 seconds on low speed, or use a sturdy spatula to fold in sugar.*
Divide dough into 12 equal parts. Shape into a rough ball. (A kitchen scale is recommended for equal portions!) Place on a parchment lined baking sheet. Cover with plastic wrap and let dough rest for 15 minutes. Meanwhile, set up waffle iron.
I use this stovetop Belgian waffle iron. Separate the two waffle iron pieces and set over medium heat. Lightly brush irons with neutral flavored oil.
Once iron is hot (about 350°F measured on an infrared thermometer), add portioned dough balls to bottom waffle iron. Attach top waffle iron. Press down on handle to distribute dough. Cook over medium heat for 3 minutes on each side. Dough may steam as it cooks. Cook waffles until golden brown and pearl sugar has melted and caramelized.
Transfer cooked waffles to a wire rack while you cook remaining dough. Serve immediately. Otherwise, cool to room temperature and store in an airtight container for up to 3 days. Waffles will lose their crunch once stored in an airtight container. Re-crisp in a toaster oven if desired.