In a small bowl, combine ½ cup of warm milk with 2 tablespoons of sugar and 2 ¼ teaspoons of instant yeast. Stir gently and let it sit for 5 minutes until frothy.

In a large mixing bowl, whisk together 3 cups of all-purpose flour and ½ teaspoon of salt. Gradually add the frothy yeast mixture along with ⅓ cup of sweetened condensed milk, 1 large egg, and 2 tablespoons of softened butter. Stir until a shaggy dough forms, then knead for about 8-10 minutes until smooth.

Shape the kneaded dough into a ball and place it in a greased bowl, covering it and letting it rise in a warm area for about 30-45 minutes.

Once risen, punch the dough down gently, transfer it to a floured surface, shape it into a loaf, and place it in a greased loaf pan. Let it rest for another 15-20 minutes.

Preheat the oven to 350°F (175°C). Whisk together 1 egg yolk and 1 tablespoon of milk to create an egg wash. Brush this over the dough, then bake for 25-30 minutes until golden brown.

Remove the bread from the oven, let it cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.