Bloom the yeast: Whisk the water, maple syrup and yeast together in a large bowl. Cover the bowl and let the yeast bloom until foamy, about 15 minutes.
7 grams active-dry yeast, 175 grams water, 14 grams maple syrup
Make the dough: Stir the sourdough discard and apple sauce until fully incorporated. Fold the flours and salt until a cohesive dough forms.
113 grams apple sauce, 113 grams sourdough discard, 400 grams all-purpose flour, 60 grams whole wheat flour, 9 grams salt
Knead the dough into the oil until completely absorbed. The dough should start greasy and gradually become smoother and less sticky. Cover the bowl with plastic wrap and let the dough rest for 10 minutes.
42 grams olive oil
** If using a stand mixer, mix the dough ingredients except for the oil. Once a cohesive dough forms, knead the dough with a dough hook and slowly stream the oil into the bowl until completely incorporated about 5 minutes.
Strengthen the dough: Turn the dough out onto a lightly floured work surface. Knead the dough by folding it in half, then pressing and pushing with the heel of your hand. Continue this process until the dough becomes smooth and elastic, about 5 to 10 minutes.
First rise: Round the dough into a tight ball, and transfer it to a clean, lightly oiled bowl. Spread oil on top of the dough to prevent it from drying out.
Cover the bowl with plastic wrap and set it in a warm place until doubled in volume, about 30 to 45 minutes. This could be longer depending on the temperature of your kitchen.
Prep: Preheat the oven to 375 F. Line a 9 by 4-inch Pullman pan (see note) with parchment paper or brush liberally with oil.
Shape the dough: Turn the dough out on a lightly floured work surface. Flatten the dough into a rough rectangle. Fold the corners of the dough towards the center. Fold the tip towards the middle of the dough. Continue rolling the dough until it forms a cylinder.
Gently glide the dough across the work surface until the top feels smooth and taut, taking care not to tear the surface. Transfer the dough to the prepared pan.
Final Proof: Cover the loaf pan with plastic wrap. Let the dough rise untouched in a warm place.
The dough should fill your pan and rise about ½ an inch above the rim, about 30 to 45 minutes. The dough should gently spring back when lightly pressed with your finger.
Bake: Bake the dough at 375 F for 40 to 45 minutes, or until the loaf is golden brown and measures about 200 F when probed with an instant-read thermometer.
Move the bread to a wire rack and let it cool for at least 30 minutes before slicing.