1. Heat milk and butter in a small saucepan over low heat until butter is melted, approximately 5 minutes. Let mixture cool until warm to the touch. 2. Meanwhile, sift flour into a large bowl, then whisk in sugar, salt, and instant yeast to combine. (Use a half-gallon or larger pitcher instead of a bowl, and later you can just pour the batter right onto the waffle iron, no ladle required.). Add the warm milk/butter mixture gradually, whisking until the batter is smooth. 3. In a small bowl, whisk eggs, vanilla, and bourbon until combined. Add egg mixture to the batter and whisk until well incorporated. Scrape down sides of bowl with rubber spatula, cover bowl with plastic wrap, and refrigerate at least 12 hours, up to 24 hours. 4. Heat waffle iron. Get the waffle batter out of the refrigerator; it'll be puffed up to about twice its original volume. Stir it to deflate/recombine. 5. Make waffles and enjoy their greatness! They're best eaten while nice and hot, so distribute them as they're done rather than standing on ceremony. Suggested toppings: butter and maple syrup; powdered sugar and lemon juice; honey and lime juice; Nutella; nothing at all.