In a small bowl, combine warm milk, sugar, and instant yeast. Let sit for 5 minutes until foamy.

In a large bowl, whisk together flour and salt. Make a well and add the yeast mixture, sweetened condensed milk, egg, and butter. Mix to combine, then knead for 8-10 minutes on a floured surface.

Shape dough into a ball, place in greased bowl, cover, and let rise in a warm place for 30-45 minutes until doubled in size.

Punch down the dough, shape into a loaf, and let rest for 15-20 minutes covered.

Preheat oven to 350°F (175°C). Prepare egg wash, brush over dough, and bake for 25-30 minutes until golden.

Let cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.