In a large mixing bowl, combine the sourdough starter discard, milk, melted butter and egg. Mix well until smooth.
Add the soft wheat flour, hard wheat flour and salt to the wet mixture. Stir until combined, forming a wet/shaggy dough.
Cover the bowl and let the batter rise at room temperature for 4 hours until it has doubled, or place in refrigerator to rise overnight.
Right before baking, gently fold in the pearl sugar until evenly distributed. If you do so sooner, it will just dissolve and you will not get the right consistency.
Preheat your waffle iron and lightly grease it if necessary.
Scoop a portion of the dough onto the waffle iron, it will be more like a shaggy bread dough than a traditional waffler batter. Bake according to your waffle iron's instructions until golden brown and crisp.
Place on a cooling rack to cool slightly. Serve warm and enjoy!
Notes
Make sure you let your dough ferment for long enough. Watch your dough to see when it had doubled.
Don't use coarsely ground flour. Otherwise your waffles may turn our tough and chewy.
Make sure to use pearl sugar. If you aren't able to get it, just go ahead and make regular waffles. Pearl sugar makes all the difference.
Don't skimp on the butter. These waffles need a good amount for their signature texture.