In the bowl of a stand mixer fitted with a whisk attachment, combine the milk, warm water, yeast and sugar. Lightly whisk together until incorporated, then let the mixture sit for 5 minutes to proof.
Once the mixture is bubbly and frothy, swap the attachment to a dough hook and add in flour, bread flour and salt. Knead until the dough starts to come together, about 3 minutes. Add in the butter and continue kneading on medium speed for 10 minutes.
Once kneaded, remove the dough from the bowl and roll it into a ball. Grease the mixing bowl and return the dough to it. Cover well with plastic wrap and let rise for 1 hour.
In the meantime, mix together the filling by combining the sugar and cinnamon together in a small bowl. Set aside.
Once the dough has risen, split it in half. Roll out one section into a rectangle of about 16x8”. Brush 1⁄2 of the butter onto it, then sprinkle 1⁄2 of the cinnamon/sugar mixture over top. Roll up and place into a greased loaf pan. Repeat with the 2nd dough section.
Let the loaves rise for 30 minutes. Preheat the oven to 350°F.
Once the loaves have risen, place them into the preheated oven on the center rack. Bake for 45 minutes, until golden and baked through.
Once baked, remove from the oven and place onto a wire cooling rack until cool. Once cooled, remove from the loaf pans and slice.
Storage: Store this bread on the countertop, sealed in an airtight container. It’s softest on day one, but it will keep for up to four days. For slightly longer storage, store in your refrigerator.Reheat: I like to slightly reheat a slice either in the toaster or microwave. If you are microwaving it, I recommend wrapping it in a damp paper towel and microwaving a slice for about 8 seconds. It will have that fresh, soft, just baked texture again!Freeze: Cool completely, then package it in plastic wrap, aluminum foil, or freezer bags. Label with the date, and freeze for up to three months. Thaw in the fridge or at room temperature, and enjoy!Bread Flour: With the higher protein count, using bread flour adds additional structure and chewiness to the bread. You can choose to use only all purpose if you prefer.Proofing the Yeast: If the yeast mixture isn’t bubbly after 5 minutes, it could be due to the temperature of your kitchen. Give it a few more minutes to see if it gets bubbly. If it doesn’t, then you will need to try again with warmer milk and water, or move the bowl to a warmer place. Rising: When the dough is rising, you may have to adjust the rise time depending on the warmth of your kitchen. For the first rise, you are wanting the dough to double in size. That may take more or less time, so keep an eye on it!Slicing: If you’re not serving right away, I recommend leaving the loaves whole. They stay fresher that way. Slice them right before you want to serve them up. A sharp, serrated bread knife does a great job of making neat slices.