Pain De Mie (Sandwhich Bread) From Starter/discard

Feed your starter with an equal amount of whole wheat flour and water. Cover with plastic wrap and let sit overnight.

Put the butter in a small sauce pan and melt over low heat. Once melted, stir in the milk to cool it down.

Add milk, butter, egg yolk if using, and the bread flour. Mix thoroughly, until smooth, cover and let sit at least 1 hour.

Add the salt and sugar. Incorporate more flour a little at a time until you have a doughy ball.

Turn out onto a floured board, sprinkle with flour, and knead just enough to make a relatively smooth ball.

Put in a banneton and do 4 fold/rest sessions with 30 minutes between.

After the last rise, press the dough out on your floured board. Roll up and pinch the seam into the roll.

Place seam side down in your oiled pan. If it comes more than halfway up, snip some off the ends. You can either shape and bake this separately on a lined sheet pan or discard it.

Let rest 10 minutes if it is too springy, then press down and out in the pan.

Snip a few cuts lengthwise down the center, this will help the loaf spread out and not just up.

Spritz your loaf with water, cover with the lid, and let rise until 1 inch from the top, 1-2 hours. (1 inch is about from the tip of your thumb to the first knuckle.)

Preheat the oven to 350 F.

If it rises enough to touch the lid, use scissors to snip some off across the top.

Spritz the loaf with water. Replace the lid.
Bake for 45 minutes. Turn out onto a cooling rack, cover with a tea towel, and let cool all the way before slicing or putting away.
*If you are baking the extra on a sheet pan, you will want to pull it out after 30-35 minutes.