In a large bowl, we combine the flour, sugar, yeast, and salt. We stir well with our flat whisk.
We stir in the milk and vanilla. We set the mixture on the counter for a few minutes before adding the butter.
We stir in the cooled butter, cover the bowl with plastic wrap, and set it on the counter for 8 hours. The mixture needs to be at room temperature at this point.
When it it almost time for dinner, we wipe the non-stick surfaces of our waffle iron with some canola oil and make sure it is clean and well-greased. We plug it in and heat according to the manufacturer’s instructions.
We separate the eggs, putting the whites in the bowl of our Kitchenaid mixer and the yolks in a small bowl. We whisk the yolks with a fork and add them to the risen batter we made 8 hours ago. We also whip our egg whites to soft peaks using the whisk attachment of the stand mixer.
We fold in the whipped egg whites with a spatula until they are almost completely incorporated.
With a ½ cup dry measuring cup, we pour the thick batter onto the pre-heated waffle iron. We close and cook for about 5 minutes—according to the directions for our waffle iron. When a waffle is done, we carefully remove it with our very clean fingers and toss it from one hand to the other to cool slightly and crisp.
We serve immediately. We could have put them in a 250° F oven, but our kids could not wait! We continue until all the waffles are cooked. We get 8-10 yummy waffles (some are smaller than others). We serve the waffles with pumpkin butter, maple syrup, apples, and whipped cream.