In a large mixing bowl, combine the all-purpose flour, sugar, salt, and instant yeast. Mix well to distribute the ingredients evenly.
In a separate bowl, mix the warm milk and condensed milk until well combined.
Make a well in the center of the dry ingredients and pour in the milk mixture and the beaten egg.
Using a wooden spoon or a stand mixer with a dough hook attachment, mix the ingredients until a rough dough forms.
Add the softened butter to the dough and continue to knead for about 10 minutes, or until the dough becomes smooth and elastic. If the dough is too sticky, you can add a little more flour, but be careful not to make it too dry.
First Rise:
Shape the dough into a ball and place it in a greased bowl. Cover the bowl with a damp cloth or plastic wrap and let the dough rise in a warm place for about 1 hour, or until it has doubled in size.
Shape the Bread:
Once the dough has risen, gently punch it down to release any air bubbles.
Turn the dough out onto a lightly floured surface and divide it into three equal portions.
Roll each portion into a long rope, about 12 inches (30cm) in length.
If you’re adding a filling, spread a thin layer of condensed milk along the length of each rope.
Braid the three ropes together and tuck the ends under to form a loaf.
Carefully transfer the braided loaf onto a baking sheet lined with parchment paper.
Second Rise:
Cover the shaped loaf with a damp cloth or plastic wrap and let it rise again in a warm place for about 30 minutes, or until it has puffed up slightly.
Preheat the Oven:
While the dough is rising for the second time, preheat your oven to 350°F (175°C).
Apply Egg Wash:
In a small bowl, beat together the egg yolk and milk to make the egg wash.
Gently brush the surface of the risen loaf with the egg wash, being careful not to deflate the dough.
Bake the Bread:
Place the baking sheet in the preheated oven and bake the bread for about 25-30 minutes, or until it is golden brown on top and sounds hollow when tapped on the bottom.
If the bread is browning too quickly, you can cover it loosely with aluminum foil to prevent over-browning.
Cool and Serve:
Remove the bread from the oven and let it cool on the baking sheet for a few minutes.
Transfer the bread to a wire rack to cool completely before slicing.
Serve the Fluffy Condensed Milk Bread as is, or toast it and spread with butter or jam for a delicious treat.
