This is the recipe I give to everyone who asks. It's not the most advanced, but it produces a good loaf consistently and doesn't require being home all day. You need: 400 g bread flour, 100 g whole wheat, 375 g water, 100 g active starter, 10 g salt.
Evening (8–9 pm): Mix flour and water, let it rest 30 minutes (autolyse). Add starter and salt, mix until combined. Stretch and fold in the bowl — pull one side up and over, rotate, repeat four times. Do this every 30 minutes for 2 hours (4 sets total). Then shape into a ball, place seam-side up in a floured banneton, cover with a plastic bag, and put in the fridge.
Morning (8–9 am): Preheat oven to 250°C with a Dutch oven inside for 45 minutes. Turn the dough onto parchment, score with a razor (one confident slash), lower into the hot pot, lid on. Bake 20 min covered, remove lid, drop to 230°C, bake 20–25 min more until deep golden brown. Cool on a rack for at least one hour before cutting. The internal temperature should hit 96–98°C. Yes, you need a thermometer.