1. Stir together warm water, 1 tablespoon sugar, and yeast in a small bowl and let stand until foamy, about 5 minutes.
2. Melt 3/4 stick butter in a small saucepan. Add milk and heat to lukewarm. Stir together yeast mixture, remaining 2 tablespoons sugar, butter mixture, bread flour, and salt in a bowl with a wooden spoon until combined well, then stir in enough all-purpose flour to make a slightly sticky dough that forms a ball.
3. Butter a large bowl. Knead dough on a lightly floured surface, kneading in more all-purpose flour if dough is too sticky, 10 minutes, or until smooth and elastic but still slightly sticky. Form into a ball and put in buttered bowl. Turn to coat with butter, then let rise in bowl, covered with plastic wrap, in a warm place 1 hour, or until doubled in bulk.
4. Butter a 13- by 9-inch baking pan. Divide dough into 20 equal pieces and roll into balls. Arrange evenly in 4 rows of 5 in pan and let rise, covered loosely, in a warm place 45 minutes, or until almost doubled in bulk. Make a deep crease down center of each row of rolls using length of a floured chopstick or side of a ruler. Let rolls rise, covered loosely, 15 minutes.
5. Preheat oven to 375 degrees F.
6. Melt remaining 2 tablespoons butter and cool slightly. Brush tops of rolls with butter and bake in middle of oven until golden, 20 to 25 minutes. Let rolls cool in pan on a rack 5 minutes. Turn out onto rack and cool to warm.

Yield: 20 servings