In a large bowl, combine warm water, warm milk, and sugar; stir to dissolve.
Sprinkle the yeast over the liquid, let sit 5 minutes until foamy.
Add the softened butter and egg to the yeast mixture and mix until combined.
Gradually add flour and salt, mixing until a shaggy dough forms.
Turn the dough onto a lightly floured surface and knead for 8–10 minutes until smooth and elastic.
Place the dough in a greased bowl, cover, and let rise in a warm place until doubled in size, about 60 minutes.
Punch down the dough, divide into two equal pieces, shape into loaves, and place into greased 9x5-inch loaf pans. Cover and let rise until doubled, about 30 minutes.
Preheat the oven to 375°F (190°C). If using, brush the tops with beaten egg for a glossy crust.
Bake for 25–30 minutes until golden brown and the loaves sound hollow when tapped.
Remove from pans and cool on a wire rack at least 30 minutes before slicing.
Notes
Store tightly wrapped at room temperature for up to 3 days or freeze slices for longer storage.