Using a wooden spoon or a stand mixer fitted with a dough hook, mix the flour, yeast and salt. Add the eggs and milk mixture and mix vigorously until the dough starts to form. Gradually add the softened butter. Knead the dough for about 5 minutes using the stand mixer, or by hand on a floured work surface. Transfer the dough to a clean, lightly oiled bowl. Cover with a slightly damp cloth and let stand in a warm, humid place for about 15 minutes.