Put the flour, yeast, sugar, and salt into the bowl of a stand mixer and whisk to combine. Attach the dough hook, pour in the milk, and add 2 tablespoons of the water.
Mix on low speed until the dough comes together, about 1 minute. This initial dough should cohere and be a bit sticky. Scrape the mixer bowl and test the dough with a fingertip. If the dough seems dry, mix in droplets more of water.
Knead on medium speed for 3 to 5 minutes, until the dough is smooth, soft, and only slightly tacky. Adjust its texture with a pinch more flour or a bit more water if necessary.
Add 1 tablespoon of the softened room temperature butter and knead on low, then medium speed, until it is completely incorporated and the dough is smooth. At first you may see dabs of butter flung onto the side of the bowl, but continued mixing will bring them back into the dough. Stop to scrape the bowl as needed.
Knead in the remaining butter in 1 tablespoon amounts, making sure each addition is completely incorporated into the dough before adding the next. Continue kneading for 2 to 3 minutes more on medium speed until the dough is smooth, elastic, but still soft and only slightly tacky.
Transfer the dough onto a smooth, unfloured surface. Knead it briefly to check its texture. If it sticks to your hands, work in just a tad more flour.
Wash and dry the mixing bowl and spritz it with cooking spray. Shape the dough into a ball and put it into the bowl. Cover tightly with plastic wrap and let the dough rise at room temperature until doubled in volume, about 1 to 2 hours, depending on the temperature of your kitchen. Test by pressing a floured fingertip about a half-inch into the dough. The depression should remain when you withdraw your finger.
Meanwhile, butter your baking pan—a 12 x 4 x 4-inch or a 13 x 4 x 4- inch Pullman loaf pan, and coat the underside of the lid lightly with cooking spray. Turn the risen dough onto your work surface and pat it out into a rectangle measuring the length of your pan and about 6 inches wide.
With a long side of the rectangle facing you, fold the top half of the dough down towards you so that the two long edges meet. Press firmly to seal. Rotate the dough up and away from you so that the seal is on top and press the edge of your palm down the length of the dough to form a trench. Fold the top half of the dough down towards you and press the long edges firmly to seal.
Turn the dough seam side down and place it into the prepared pan. Using your knuckles, pat the dough out flat to fill the corners. If the dough resists at all, cover the pan for 10 minutes with a towel to relax the dough and repeat the action. The pan will be about one-third full.
Drape the pan loosely with a kitchen towel and let the dough rise again until the center of the loaf is about 1/2-inch below the rim of the pan, about 1 hour. A half hour or so before the dough is ready to bake, adjust an oven rack to the lower third position and preheat the oven to 425 degrees F.
When the dough is ready to bake, remove the kitchen towel and slide the top of the Pullman pan in place to cover it completely. Place the pan in the oven and bake for 45 minutes.
Take the pan out of the oven with oven mitts. Carefully and slowly slide the lid off the pan. The loaf will have a completely flat top and be a beautiful deep brown color. Unmold the bread and let it cool completely on a wire rack.
When completely cool wrap the loaf in a plastic bag and let it stand at room temperature overnight before slicing and eating.
Variation: Rather than bake the loaf in a Pullman pan, you can bake the dough in a standard buttered 9 x 5 x 3-inch bread pan. Pat the risen dough into a 9-inch long and 6-inch wide rectangle. Shape as described above and place into the pan seam side down. No need to knuckle it in flat. Simply cover the pan with another pan the same size to give the bread space to rise. When the bread has domed up about 1- inch above the rim of the pan, it’s ready to bake. This rise may take an hour or more, depending on the room temperature. To bake, adjust an oven rack to the lower third position and preheat the oven to 375 degrees F about a half hour before the bread has completed its rise. Uncover the loaf, put the pan in the oven, and bake for 40 to 45 minutes, until well-browned and an instant-read thermometer inserted into the center of the loaf reads 200 degrees F or a bit higher. Remove the bread from its pan, set it on a cooling rack, and cool completely. Wrap in plastic when completely cool. Storage:This bread keeps, well-wrapped, for a few days at room temperature, and it’s great for sandwiches and canapés. It freezes beautifully for up to 2 months. Thaw in its wrapping, then unwrap and slice.