Give your sourdough starter a feeding 6-12 hours before making the dough for an active, bubbling starter.
In a small saucepan over low heat, combine milk and honey. Whisk until honey is dissolved and milk reaches about 90°F. Set aside to cool slightly.
1 cup (235 grams) whole milk, 1 ½ tablespoons (30 grams) honey
In a large mixing bowl, whisk together bread flour, whole wheat flour, and kosher salt. Add the warmed milk-honey mixture and sourdough starter.
1 ¾ cups (210 grams) bread flour, 1 ¼ cups (150 grams) whole wheat flour, 2 ½ teaspoons (7 grams) kosher salt, 6 tablespoons (75 grams) active sourdough starter
Use your hands to mix until a cohesive, slightly shaggy dough forms and there's no dry flour visible. Cover the bowl with a damp towel or plastic wrap and let it rest for 30 minutes.
After 30 minutes, perform your first set of stretch and folds. Do this by dipping your hand into a bowl of water before grabbing one edge of the dough and pulling it up as far as it will stretch before folding it over onto itself. Rotate the bowl 90 degrees and repeat. Repeat this stretching and folding around the dough two more times (for a total of 4 times). Then, gently flip the dough over so that the fold side is now facing down. Cover and allow the dough to rest for 30 minutes before performing another set of stretch and folds. Perform 4 sets of stretch and folds in total.
Let the dough rise until it's noticeably puffy and roughly doubles in size. This takes about 4 hours at 75°F.
Generously coat the bottom and sides of a pie plate or cake pan with butter. Turn the dough out onto a lightly floured surface and divide into 12 equal pieces, about 57 grams each. Take each piece, bring its edges to the center, and shape them into balls. Roll the creased side around the counter to seal it. Place the dough balls equally spaced into the prepared pan.
Unsalted butter
Cover the rolls and allow them to proof for 1-2 hours, or until they look noticeably puffy.
About 20 minutes before they're done proofing, preheat the oven to 375°F. Bake for 25-30 minutes or until the tops turn a light golden brown and the internal temperature of the rolls reaches 190°F. If the tops are browning too quickly, cover them loosely with foil.
Remove the rolls from the oven, immediately brush with melted butter, and sprinkle with kosher salt. Let them cool for 5-10 minutes before serving. Enjoy!
Extra melted butter and kosher salt