Place the butter in the bowl of a standing mixer fitted with the paddle attachment. Pour the warm water over the butter and let stand for 5 minutes. With the mixer on low, add 3/4 cup of the flour, the dry milk, sugar, salt, the herbs and pepper, and mix until a soft batter is formed. Add enough of the remaining flour in 1/4 cup increments until the mixture just comes together to form a ball of dough.
Change the attachment on the mixer to a dough hook and knead the dough for 3 minutes. (Alternatively, knead dough by hand on a flat, lightly floured surface for 3 minutes.) If the dough is still a bit sticky, add a sprinkle of flour or two.
Place the dough in a bowl and cover with plastic wrap. Allow to sit at room temperature for 1 hour.
Preheat the oven to 400 degrees F.
Place the dough on a lightly floured work surface and roll to form an approximately 16 by 19-inch rectangle. The dough should not be any thicker than 1/8-inch. Pull gently if necessary to form a rectangle. Sprinkle the dough with kosher salt and, using your hands, gently press the salt into the dough. Cut the dough with a sharp knife or a pastry wheel into irregular, rectangular pieces, about 1 1/2 inches wide and 3 to 4 inches long. (Alternatively, the crackers may be cut into any desired shape.) Using the tines of a fork, prick each piece of dough 4 to 5 times.
Transfer to ungreased baking sheets and bake for 11 to 13 minutes, or until the crackers are light golden brown with some lighter spots, checking midway through the baking time and rotating crackers as necessary for even cooking. Be careful; these will burn quickly if not watched closely. Cool the crackers on a wire rack and store in airtight containers for days. These crackers also freeze well.