Crush the lumps of dry milk and make it powder-like. Put bread flour and dry milk in a large bowl, and stir well. Make a dent and put sugar and dry yeast into it.

Warm water until it reaches 40℃ / 104 F. (Microwave at 600W for 30-50 seconds.) First, pour lukewarm water over the sugar and dry yeast, and then pour over the flour while drawing circles. Roughly mix with a spatula until the dough almost comes together. Add salt and mix roughly.

Put the dough in a stand mixer. (I used KitchenAid Artisan 3.3L.) Knead it for 2-3 minutes at speed 2. Then knead for 10 minutes at speed 3-4 until smooth. In the middle of kneading, remove the dough from the hook, and turn it over. (Knead for 5 minutes, turn over and knead again for 5 minutes.)

Add the softened butter. Knead it for 2-3 minutes at speed 2. Then knead for 10 minutes at speed 3-4 until smooth. In the middle of kneading, remove the dough from the hook, and turn it over. (Knead for 5 minutes, turn over and knead again for 5 minutes.)

Use your hands to stretch gently one part of the dough thinly. It's ready if it doesn't tear. Put onto a work surface. Use your hand to hit the dough against the work surface. Fold in half. Repeat it 50-100 times.

Shape it into a ball and put it in a lightly oiled bowl. Cover it with cling wrap and let it rise at 35℃ / 95 F (or a warm place) for 1 hour until 1.5 times in size.

Put it out on the work surface and press it gently to remove the air. Fold the top third of the dough down, then the bottom third up. Rotate it 90 degrees and tri-fold it again.

Shape it into a ball and put it back in the bowl. Cover it with cling wrap and let it rise at 40℃ / 104 F (or a warm place) for 30-60 minutes until 1.5-2 times in size.

Finger Dent Test! Press your floured finger into the dough. It's ready if the dent springs back a little and it stays without filling in. Press it gently to remove the air.

Divide it in half. Punch down, and shape each into a ball.

Cover with a tightly wrung wet cloth and leave for 20 minutes. Punch down to flatten. Turn it over and fold it in half. Rotate it 90 degrees and fold it in half again.

Shape them into balls. (Please make the surface smooth and elastic.) Pinch the seams to stick together. Place two balls in a lightly oiled loaf pan with the seam side facing down.

Let it rise at 40℃ / 104 F (or a warm place) for 60-90 minutes until the top of the dough is higher a little than the height of the pan. Preheat the oven to 220℃ / 428°F. Spray water lightly (omittable). Bake it at 220℃ / 428 F for 15 minutes and 200℃ / 392 F for 15 minutes until deep golden brown. Drop the pan to prevent shrinkage. Remove the bread from the pan and cool it down on a rack.