Cover the bowl with plastic wrap or a damp, lint-free cotton towel and let the dough rest for 20 minutes to allow it to fully hydrate before further kneading. Turn the speed to medium-low and continue to knead until the dough is firm, elastic and smooth, 3 to 6 minutes. (NOTE: To mix by hand, combine the flour and the salt in a large bowl, add the yeast and milk mixtures, and mix until a dough forms. Turn out onto a work surface and knead until firm, elastic, and smooth, about 8 to 10 minutes.)