In a mixer add all of the liquid first and mix on slow.
Add the dry ingredients and mix on slow until mixed together for 4 minutes
Bring up to medium speed and mix until you hear thumping against the sides. Add diced butter and continue mixing for an additional 10 minutes. The dough should be glossy and wrapped around the dough hook.
Turn out onto a floured countertop and gently knead into a ball. Lightly wrap with plastic wrap and let proof in the fridge for at least 12 hours and maximum 24 hours.
Grease each loaf pan with butter and set aside.
Roll out the dough and degas. Divide the dough into 12 equal sections.
Flatten each section into a flat rectangle then fold each side into the middle. Flip over.
Using the palm of your hand to cup the ball against the countertop. Move your hand in a circle, pulling the dough into a tight ball.
Once all of the dough is rolled, place 6 balls in each loaf pan, positioning them 2 x 3.
Brush with egg wash and cover. Let proof for 1½ hours at room temperature or until doubled in volume.
You can speed up this process by putting a pan of boiling water in the bottom of your oven, creating a proofing chamber. Then place the bread pans in the oven to let proof.
Once the loaves are proofed, preheat the oven to 180°C (355°F). Bake for 20 minutes or until the center of the loaf registers at 95°C (200°F)
Let cool for 10 minutes before removing from the pan to cool further.