From Williams-Sonoma Essentials fo Breakfast & Brunch by Chuck Williams (ISBN-13 978-0-8487-3192-2 or ISBN-10 0-8487-3192-1). They suggest serving with a strawberry-rhubarb compote. Time does not include refrigeration.
In a large bowl, dissolve yeast and granulated sugar in warm water and let stand until foamy, about 5 minutes.
In a saucepan over low heat, combine the milk and butter and heat to lukewarm (about 115 F/46 C).
In a small bowl, whisk together flour, brown sugar, and salt.
Stir warm milk mixture into the dissolved yeast. Add flour mixture and stir until blended. Cover the bowl and refrigerate overnight. The batter will thicken slightly.
To cook waffles, preheat waffle iron for 5 minutes, then brush with oil. Stirr egg and baking soda into the chilled batter until blended. Following manufacturer's directions, ladle batter for 1 waffle into the center of the waffle iron (usually 1/2 cup). Spread with a small spatula to fill any holes. Close waffle iron and cook until steam stops escaping from the sides and top opens easily, or according to manufacturer's directions, 4-5 minutes. The waffle shoudl be browned and crisp.
Repeat with remaining oil and batter. Transfer waffles to warmed patter and serve at once with desired toppings.