• Levain or active starter. To prepare a levain add 30 grams of active starter to a jar, along with 35 grams of flour and 35 grams of water. Stir, cover, and allow it to sit at room temperature until it has reached its peak (about 4-8 hours). Note: If your home is very warm (or your starter doubles in less than 8 hours), use 14 grams of starter, 43 grams of flour, and 43 grams of water.

Forming the Dough:

• Add the active sourdough starter, sugar, salt, and water to the bowl of a stand mixer (or a large mixing bowl). Using the whisk attachment of your mixer (or a handheld whisk), stir everything together until it appears milky.
• Slowly pour in the cooled melted butter, whisking as you go.
• Add in 2 cups of flour (about 240 grams), and stir until it is incorporated.
• Switch to the dough hook (or if by hand, a dough whisk or rubber spatula), and add the flour about ½ cup (60 grams) at a time, mixing to incorporate it. If doing so without an electric mixer, you may need to switch to doing this by hand (I recommend wetting your hands with warm water to prevent sticking).
• The dough should be sticky, but not loose. Add enough flour that the dough comes together, but not so much that it’s firm.
• Once the flour has been incorporated, knead using the dough hook attachment for 2 minutes. The dough should pull away from the edges; if it is sticking to the bowl, add a little more flour until it comes together. Once the dough is soft and not sticky to the touch it’s ready for the next step.

  If making by hand: Turn the dough out onto a lightly floured countertop and knead for 5 minutes. You will know the dough is ready when the dough is soft and pliable - not sticky.

Bulk Rise:

• Lightly oil a large glass bowl, and add the dough to the bowl. Turn it over to cover it in the oil.
• Cover the bowl tightly and allow it to rise for 8-12 hours (or until nearly doubled in size). Note: The amount of time it takes to rise will depend on the temperature of the room the dough is rising in and how active your sourdough started out as.

Shaping and Final Proof:

• Lightly oil a loaf pan, and line it with parchment paper (cut to size). Set aside.
• Turn out the proofed dough onto a clean, lightly floured surface.
• Flatten the dough into a large rectangle that’s about 1” thick (this doesn’t need to be precise and you want to avoid removing all of the air from the dough. I gently flatten the dough with my fingers and pull the dough out to create a rectangle).
• Next, roll the dough up about halfway, then turn in each side and finish rolling the dough up into a cylinder. Tuck in any edges.
• Transfer the dough to the prepared loaf pan. Cover (using plastic wrap or a damp tea towel) and allow to rise for 1-1 ½ hours (until the dough fills in the bread pan).
• With about 15 minutes left of the final proof, preheat the oven to 375ºF (190ºC) and position the rack one spot lower than the middle (this will prevent the top from browning too quickly).
• Uncover the dough and place it in the oven. Bake at 375ºF (190ºC) for about 40 minutes. You will know it is done when it reaches a minimum internal temperature of 190ºF (88ºC). The loaf will be golden brown and hollow sounding when it is tapped on the bottom.
• Remove from the oven and allow the bread to cool in the pan for 15 minutes.
• Remove the bread from the loaf pan and place on a cooling rack. Allow the bread to cool for at least 30 minutes before slicing, although 2 hours is ideal.