In the bowl of a stand mixer fitted with a dough hook, combine the flour, sugar, yeast and salt and mix for a few seconds, just until evenly combined.
Add egg and milk. Turn the mixer on low speed and knead for 5 minutes.
Add soft butter, increase speed to the next level and knead until dough firms up into a mass around the hook (it should still be sticking to the bottom of the bowl), 8–10 minutes.
Lightly butter the inside of a bowl. Use your hands to lift dough out of mixer bowl, shape into a ball and place in prepared bowl. Cover with a kitchen towel and let rise in a warm place until doubled in size, 40 to 60 minutes.
Punch the dough down and use your hands to scoop it out onto a surface. Using a bench scraper or a large knife, cut dough in half. Lightly form each half into a ball, cover again and let rise 15 minutes.
Using your hands, flatten the first ball of dough into a 10×6″/ 25.5×15 cm rectangle. Fold a third of the dough lengthwise over toward the center, then do the same thing from the other side. Fold the two edges of the loaf and press lightly ( view photos in step by step section). Transfer the loaf seam-side down, into a lightly buttered 10×4.5″/ 25.5×11.5 cm loaf pan. Do the same with the second ball of dough.
Cover the pans loosely with lightly greased plastic wrap or a kitchen towel, and allow the bread to rise for about 30-40 minutes, until it’s domed about 1″ above the edge of the pan.
Meanwhile, arrange a rack in the bottom of the oven and heat the oven to 350°F/175°C.
Bake the loaves for 20 to 25 minutes, until they become a light golden brown. When ready, remove loaves from their pans and allow them to cool on a wire rack.
