Liege Waffles, from the Belgian city of Liege, are made with a brioche-type yeast-leavened dough and Belgian pearl sugar. Liege waffles are slightly crunchy on the outside from caramelized sugar and flaky and buttery on the inside. They are flavored with vanilla and speckled with crunchy bits of pearl sugar throughout. Enjoy these indulgent waffles for breakfast, dessert, or a snack. Liege waffles are sweet enough to eat without any topping, but a little Nutella or melted chocolate never hurts.
Put milk in a glass measuring cup or other microwave-safe container and microwave until milk is warm, but not too hot. Add milk, brown sugar, and yeast to the bowl of a stand mixer. Stir by hand to combine. Wait 10 minutes, or until yeast is frothy.
Add eggs, egg yolk, and vanilla and stir by hand to combine.
Put the dough hook attachment on your mixer. Add 3 1/2 cups flour to bowl and mix with the dough hook (should be on speed 2 for KitchenAid) for 3-4 minutes, until dough comes together into a ball. Scrape down the sides halfway through mixing.
Cut the butter into 2 tablespoon-sized chunks (7 pieces). Add butter to the dough and continue to mix with the dough hook on low speed until butter is completely combined into the dough. This will take 5-10 minutes. Scrape down sides as needed. The dough will be very sticky.
Cover bowl with plastic wrap. Let rise in a warm place at room temperature until doubled in size, about 1 ½ hours.
Dust a workspace with flour and flour your hands. Empty dough onto workspace. Flatten ball of dough into a circular shape. Add all the pearl sugar to the middle of the dough. Fold over and knead by hand until the pearl sugar is incorporated throughout the dough.
Preheat oven to 200 degrees.
Divide the dough into individual pieces (1 for each waffle). Each waffle should use 3-4 ounces of dough. I measure out the first few with a scale and then eyeball the rest. Roll each piece into a ball and place on a lightly floured plate.
Preheat waffle iron. Grease waffle iron only if indicated by manufacturer’s instructions. Cook each waffle according to waffle iron instructions. I used a nonstick ceramic Belgian waffle maker, and it took about 4 minutes per waffle. If you notice sugar burning at any point, unplug the waffle iron to let it cool down before continuing. After each waffle is cooked, place in oven to keep warm until ready to serve. Be careful handling cooked waffles – the melted caramelized sugar is very hot.