This method still mostly follows Ken Forkish's for his Overnight Country Brown but I've adapted it for daytime bulk fermentation and with overnight cold retard to make it more friendly to warmer temperatures.
Day 1, Morning, Feed the levain: Take 30 grams of your mother starter and feed it 30 grams each flour and water. You can add feeding amounts of flour and water by five grams each just to make sure you have exactly 90 grams to use for the recipe without worrying about having to scrape every little bit from your jar. Alternatively, you can also feed your starter the night before and it will be ready to use in the morning.
Day 1, Midday, Mix the Flours and Water: In a bowl, mix the flours and water (NOT the starter and salt) and stir with a spatula or dough whisk until no dry bits of flour remain in the bowl. Cover with plastic wrap and autolyse for 30 minutes (if your starter is not ready to use after 30 minutes you can extend the autolyse stage up to a few hours).
Day 1, Add the Salt and Levain and first Stretch and Fold: After autolyse and your starter is ripe, add it and the salt to the flour/water mixture. Use wet hands to knead the starter and salt in until they've been evenly incorporated in the dough (this could take about three minutes) and use this stage to also perform the first stretch and fold session. Cover with plastic wrap and wait 30 minutes. Bulk fermentation starts at this stage.
Day 1, Stretch and Fold, continued: Perform three more stretch and fold sessions every thirty minutes.
Day 1, Bulk Fermentation, continued: After the four stretch and fold sessions keep the dough covered and allow for bulk fermentation to proceed until has doubled or nearly doubled in size. From experience, bulk fermentation is roughly five to six hours in low to mid 70ºF temperatures. It's a good idea to use a digital thermometer to check the temperature of your dough and it's also a good idea to err on the consvative side and under -ferment rather than fermenting too long. The dough will be bubbly on top and light and jiggly when done. Remember that bulk fermentation starts as soon as you add the levain to your dough. (Fermentation time is driven by temperature and other variables so just use this range as a guide. If you use the whole wheat flour in the recipe look towards the lower range of fermentation time.)
Day 1, Evening, Shape and Cold Retard: (You have two options after bulk fermentation. You can shape, transfer the dough to a banneton and refrigerate overnight and bake the next day. The other option is to refrigerate the dough still in the bowl, shape in the morning and bake. I recommend shaping before refrigeration as it's easier to score and more convenient to bake the loaf when it's cold.) To shape: Transfer the dough to a lightly floured surface. The dough will relax and flatten when you take it out of the bowl. Taking one section of dough at at time, fold the sections over the rest of the dough until you have a somewhat tight ball shape. Then tighten the dough by pulling it towards you by cupping the dough with both your hands using your pinky fingers as the anchors. This tightens the dough shape as you pull it towards you. Rotate then repeat three to four times until the dough holds its ball shape. Transfer the dough on a floured banneton with the seam side down. (Note: Ken Forkish instructions in the book recommend seam side down so that when you turn the dough out to bake the seam becomes the top of the loaf and you don't have to score before baking. These days I prefer putting the dough in the banneton seam side up so that when I turn the dough out to bake the seam is down and I score the top of the loaf. Do what makes you more comfortable.) After shaping, put the banneton in a plastic produce bag and refrigerate overnight. The overnight refrigeration retards the fermentation process and avoides overproofing the dough. From this point you can bake in the morning or extend cold retard longer to suit your schedule. You can store your dough in the fridge up to a few days. If you choose to shape on the day you bake, just refrigate the dough in the bowl after bulk fermentaion and follow the shaping steps above when ready to bake the following day.
Day 2, Bake: This recipe uses a dutch oven for baking. Place your dutch oven with the lid on in the oven and preheat to 475ºF. Once the oven has reached temperature, invert the dough on a piece of parchment paper. I like to use a small cutting board, line it with parchment, lay it on top of the banneton and flip to invert the dough. If you transferred the dough to the banneton seam side up, you will need to score the dough to allow for expansion before baking it. If you transferred the dough seam side down into the banneton you don't need to score. Make sure you have oven mitts then take the (very hot) dutch oven out of the oven and place on the stove. Remove the lid and rest one of your mitts on top of the lid so you don’t touch it by accident. Take the ends of the parchment paper and carefully lift and transfer the dough to the dutch oven. Cover the dutch oven and place it back in the oven. Bake covered for 30 minutes then uncover and bake for another 20 minutes, checking your bread at the 15-18 minute mark just in case your oven runs hot. When done, tilt the bread out of the dutch oven and let it cool on a rack for at least two hours before slicing.