Step 1: In a large bowl or the bowl of a stand mixer, combine warm milk, warm water, and granulated sugar. Sprinkle the active dry yeast over the liquid and let it sit for 5-10 minutes, until frothy. If it doesn't foam, your yeast may be old; start over with new yeast.
Step 2: Add 4 cups of the all-purpose flour and salt to the yeast mixture. Mix with a spoon or dough hook until a shaggy dough forms. Add the softened butter and continue to mix.
Step 3: Knead the dough for 8-10 minutes using a stand mixer with a dough hook on medium-low speed, or by hand on a lightly floured surface, until the dough is smooth, elastic, and passes the windowpane test (you can stretch a small piece thin enough to see light through it without tearing). Add more flour, a tablespoon at a time, if the dough is too sticky.
Step 4: Lightly grease a clean large bowl with oil. Place the dough in the bowl, turning once to coat. Cover the bowl with plastic wrap or a clean kitchen towel and let it rise in a warm, draft-free place for 1-1.5 hours, or until doubled in size.
Step 5: Gently punch down the risen dough to release the air. Transfer it to a lightly floured surface and shape it into a log. Place the dough log seam-side down into a lightly greased 9x5 inch loaf pan.
Step 6: Cover the loaf pan with plastic wrap or a kitchen towel and let it rise again in a warm, draft-free place for another 30-45 minutes, or until nearly doubled in size.
Step 7: Preheat your oven to 375°F (190°C) during the last 15 minutes of the second rise. Bake the bread for 30-35 minutes, or until the top is golden brown and the internal temperature reaches 200-210°F (93-99°C).
Step 8: Remove the loaf from the oven and immediately transfer it to a wire rack to cool completely before slicing. This prevents the bread from becoming gummy.