Toast the walnuts

• Preheat the oven to 325 °F (165 °C). Add the walnuts to a baking pan in a single layer.
• Toast the walnuts, tossing as needed, until lightly golden and aromatic, about 10-14 minutes. Allow to cool completely.

Mix yeast and liquids

• In the bowl of a stand mixer, add the warm water, yeast, salt, walnut oil, and maple syrup.
• Whisk until combined and the salt is dissolved. Let rest for 5-7 minutes until the mixture is slightly foamy.

Mix in the flour

• Add the flour to the mixer bowl. Mix on the lowest “stir” setting for 2 minutes (or mix by hand) until no dry flour remains.
• Scrape the sides of the bowl as needed. Cover with plastic wrap or a lid and allow to rest for 10 minutes. The dough will look rough and feel soft, but not sticky.

Knead the dough

• Knead on mixer speed 2 for 5-6 minutes (or by hand for 10-12 minutes) until the dough is smooth and elastic. It should clean the sides of the bowl but may cling lightly to the bottom. If too dry, add water 1 teaspoon at a time; if sticky, add flour 1 teaspoon at a time.
• To test for doneness, do the windowpane test: pinch off a walnut-sized piece of dough and stretch it slowly; if you can see light through the dough before it tears, the gluten is developed.

Add the walnuts

• Sprinkle the cooled walnuts over the dough. Mix on the lowest stir speed for 45-60 seconds just to distribute. If the walnuts don’t incorporate well this way, it may be easier to quickly knead them in by hand. Stop when the walnuts are evenly mixed in, and the pieces remain large.
• Cover with plastic wrap or a lid and let rest for 10 minutes.

Bulk fermentation

• Transfer the dough to a lightly oiled bowl. Cover with plastic wrap or lid and ferment about 90 minutes at about 70 °F (21 °C), until the dough is soft, puffy, and has risen to about 1½ times its original size.
• (You can do an optional fold at 45 minutes for extra strength: lift one edge and fold it into center; repeat on all 4 sides.)

Shape

• Lightly flour the counter and turn out the dough. Pat it gently into a rectangle, and fold one side like a letter into the center. Fold the other side over the first, and then roll it up to form a tight boule.
• Build structure and tension by pushing the sides down into the bottom as you rotate it. (It may be helpful to use a bench scraper to help you push the sides under as you go.) Continue to rotate for a minute or so, tucking the sides under until the boule has some firm tightness. Turn the boule over and pinch the seams tightly together.
• Place seam-side up in a floured banneton (or seam-side down on parchment paper in a baking pan). Cover with plastic wrap.

Final proof

• Let the dough rest for 45-60 minutes at room temperature. A gentle finger press should spring back slowly, leaving a slight indentation. This means it’s ready to bake.

Bake

Baking option 1 - Dutch oven (yields best bottom color)

• Preheat a dutch with its lid to 475 °F (245 °C) for 30 minutes.
• Place the dough seam side down onto silicone bread sling or parchment. Using a baker’s lame or sharp knife, score the dough about ½ inch (1.3 cm) deep, lower into the pot, and cover with the lid.
• Bake covered for 20 minutes. Reduce the heat to 425 °F (220 °C), and bake uncovered for an additional 18-22 minutes until deeply golden with a firm crust. The bottom should sound hollow when tapped.

Baking option 2 - Baking stone/steel method

• Place a baking steel or stone on the lower-middle rack, and add an empty baking pan with sides to the rack below. Preheat to 500 °F (260 °C) for 30 minutes.
• Add the loaf to a large piece of baking parchment. Using a baker’s lame or sharp knife, score the dough about ½ inch (1.3 cm) deep. Keeping the loaf on the parchment, place it onto the stone. Pour 1 cup of boiling water into the lower baking pan and quickly close the oven door.
• Bake for 10 minutes; remove the parchment, reduce the heat to 425 °F (220 °C), and bake for an additional 20-25 minutes, until deeply golden with a firm crust. The bottom should sound hollow when tapped.

Cool

• Let cool on a baking rack for at least 1 hour. Although tempting, if you cut it early, the crumb will likely compress.