Warm the milk, water and butter in a saucepan or microwave-safe bowl until the butter has melted. Stir to combine, then let it cool until lukewarm. 300 g whole milk, 140 g butter
Add the water, sugar, and yeast. If using active dry yeast, let it sit for 5 minutes until foamy. If using instant yeast, you can continue straight away. 240 g water, 25 g granulated sugar, 7 g instant yeast
Add the flour, egg yolks and salt. Whisk or stir until the batter is mostly smooth. A few small lumps are fine. 375 g all-purpose flour, 3 large eggs, 1/4 tsp of salt
Whip the egg whites until soft peaks form, then gently fold them into the batter. A few streaks of white are fine.
Cover the bowl and leave the batter to rise at room temperature for about 1½ to 2 hours, or until doubled and bubbly.
Preheat the waffle maker until hot and lightly grease it if needed.
Pour in about ½ cup of batter per waffle, or the amount recommended for your waffle maker. Cook for 3 to 5 minutes, until golden and crisp on the outside and light inside.
Serve the waffles straight away while they’re still crisp. They’re delicious with powdered sugar, cream, or fresh fruit.