This recipe is from The Fannie Farmer Cookbook (Alfred A. Knopf, 1996), which was edited—and largely rewritten—by culinary Renaissance woman Marion Cunningham. Following Marion's advice, we suggest using a conventional waffle iron, not a Belgian-waffle maker (which can produce deeper crevices than desired).
1 7-gram package active dry yeast
2 cups warm milk
8 tbsp. butter, melted
1 tsp. salt
1 tsp. sugar
2 cups flour
1⁄4 tsp. baking soda
1. Dissolve yeast in 1⁄2 cup lukewarm water in a large bowl and set aside until foamy, 8–10 minutes. Add milk, butter, salt, sugar, and flour and beat with an electric mixer on medium speed until well combined, 2–3 minutes. Cover with plastic wrap and set batter aside, at room temperature, overnight.
2. The following day, preheat an electric waffle iron. Whisk eggs and baking soda into batter until thoroughly combined (batter will be very thin). Pour 1⁄2 cup of the batter into hot waffle iron and let batter set for 30 seconds, then lower waffle iron lid and cook until waffle is golden brown and crisp, about 5 minutes. Repeat process with remaining batter. Serve with maple syrup and butter, if you like. Batter will keep for several days in the refrigerator.