Combine lukewarm water and malt extract (or brown sugar) in a large mixing bowl; sprinkle yeast on top and let stand until the yeast is dissolved, about 5 minutes. Gradually stir in 3 cups flour, stirring in the same direction for 3 minutes. Stir in dry milk and salt. Then gradually add more of the remaining flour until the dough becomes too difficult to stir.
Turn the dough out onto a lightly floured surface and knead, gradually incorporating more flour as needed to prevent sticking, until smooth and elastic, about 10 minutes. (Alternatively, the dough can be kneaded in a stand-up mixer fitted with a dough hook.)
Place the dough in a lightly oiled bowl, turn to coat and cover with plastic wrap. Let rise until almost tripled in volume, 2 1/2 to 3 hours. Punch dough down; cover and let rise until doubled, about 1 1/2 hours. (Alternatively, you can let the dough rise for the second time overnight in the refrigerator.)
Lightly oil 2 baking sheets or coat with cooking spray; sprinkle with cornmeal. Punch the dough down, turn out onto a lightly floured surface and knead into a smooth ball. Divide the dough into 16 portions. Shape each portion into a ball, then roll to make a slight oval. (As you work, keep any dough that you are not using covered.) Place the rolls at least 2 inches apart on the prepared baking sheets. Sprinkle the rolls with flour and rub gently over the surfaces. Cover with a dry tea towel and let rise until almost doubled, about 1 hour.
Thirty minutes before baking, place a baking stone or an inverted baking sheet on the center rack of a cold oven. Place a metal cake pan on the bottom rack; preheat to 425°F.
Just before baking, pour 1 cup water into the cake pan. Working with one batch at a time, cut a 1/4-inch-deep slash with a serrated knife along the top of each roll. Place the baking sheet on the baking stone or inverted baking sheet and bake until the rolls are golden brown and bottoms sound hollow when tapped, 15 to 20 minutes. Transfer to a wire rack and let cool. Add more water to the cake pan, slash the remaining rolls, and bake them in the same manner.
Make Ahead Tip: Store in a plastic bag in the freezer for up to 3 months. To serve, arrange the frozen rolls on a baking sheet and heat in a 350°F oven for 10 to 15 minutes.
Malt extract feeds the yeast and gives the rolls a lovely golden hue. The extract can be found in health-food shops and stores where beer-making supplies are sold.
Storage smarts: For long-term freezer storage, wrap your food in a layer of plastic wrap followed by a layer of foil. The plastic will help prevent freezer burn while the foil will help keep off-odors from seeping into the food.