Bloom the yeast. In a small bowl, stir the warm milk with the yeast and 1 tsp of the sugar. Let it sit for 5–10 minutes, until foamy on top. If nothing happens, your milk may have been too hot or the yeast inactive. Try again with a fresh packet.
Make the dough. In the bowl of a stand mixer, combine flour, salt, and the remaining sugar. Add the eggs, vanilla, and the milk-yeast mixture. Mix with the dough hook on low until a shaggy dough forms, about 1–2 minutes. Scrape the bowl if needed.
Knead and add butter. Keep mixing on medium-low until the dough starts to look smoother, about 3 minutes. Now add the softened butter a tablespoon at a time, letting each piece disappear before adding the next. The dough will look slippery at first. Keep going. After 5–7 minutes it should become glossy and elastic. It will be soft and slightly sticky, that’s right where it should be.
First rise. Cover the bowl and let the dough rise in a warm spot until puffy and nearly doubled, 60–90 minutes. If your kitchen is cool, give it a little more time. No rush.
Chill briefly. Slide the bowl into the fridge for 20–30 minutes. This short chill makes it easier to fold in the pearl sugar and portion without sticking like crazy.
Fold in the pearl sugar. Sprinkle the sugar over the dough and gently fold it in with a spatula or your hands until it’s evenly distributed. Try not to crush the pearls too much.
Portion and rest. Turn the dough onto a lightly greased surface. Divide into 10 equal pieces, about 90–100 g each. Shape into loose balls, cover, and let rest 15–20 minutes. This little pause helps them relax so they cook evenly.
Preheat the waffle iron. Medium to medium-high heat is the sweet spot. Lightly grease the plates with oil or a thin swipe of butter. If your iron runs hot, go a notch down. Caramel burns if rushed.
Cook. Place one dough ball in the center of the iron and close the lid without forcing it. Cook 3–5 minutes, until deep golden with caramelized edges. Peek once around the 3-minute mark. Every iron is different, so the first waffle is your test round.
Cool and repeat. Lift the waffle out with tongs and set it on a wire rack. Careful, the sugar is molten and sticks. A sheet of parchment under the rack catches drips and saves cleanup. Keep cooking the rest, re-greasing the iron lightly as needed.