Add 300 grams (1 ½ cups) of warm water to the bowl of your stand mixer, along with 100 grams of active sourdough starter. Using the whisk attachment, mix slowly to combine until the liquid appears milky.
Next, add the honey and salt, whisk to combine. Note: If your honey is stiff, try heating it first.
Add 2 cups of the bread flour and mix until incorporated. Then, add ¼ cup of softened butter and mix until fully combined.
Replace the whisk attachment with the dough hook attachment.
Slowly add the remaining flour by adding about ⅓ cup at a time, allowing the flour to become fully incorporated before adding more. *The dough will still stick to the sides of the bowl, but hold its shape.
Set your stand mixer to medium speed. Knead the dough using the dough hook for 3-5 minutes (6-8 minutes if doing it by hand), or until the dough begins to come away from the sides of the bowl. The dough should be soft, but it may still stick to the bottom of the bowl. That’s okay! The dough should be slightly sticky/tacky – it’s a good sign that it will not be too dense once baked.
Cover the bowl tightly with plastic wrap (or a damp kitchen towel) and allow to ferment at room temperature until it roughly doubles in size, about 8-12 hours. Note: The time can vary depending on the temperature of the room and how active your starter is. The best indicators are a dough that nearly doubles in size, and springs back when gently pressed with a thumb.