@jwilliams35 I’m glad you like the details and options in the recipe. I tend to bake the recipes so many times and in so many ways, I figure why not share the info (though I do sometimes worry about word-clutter).
@Elizabeth_Levy I don’t know how buttermilk would perform for the tangzhong or the final dough, but I can’t imagine it would be a problem, so I’d certainly try it. I have to admit to being one of those people who adds vinegar or lemon juice to regular milk every time a recipe calls for buttermilk so I’m not all that well-versed in using it. I’ve used whey and kefir milk in various breads.