In a bowl, combine milk, sugar, salt, and butter. Stir until sugar and salt are dissolved. Warm in microwave until luke-warm. Remove from microwave and add the egg and beat several times until well blended.
In a big bowl, mix together flour and yeast. Pour in the liquid mixture over the flour and mix until a dough forms. Knead the dough on a clean surface dusted with flour until it becomes smooth and elastic, about 7-10 minutes.
Form the dough into a ball and place the dough in a greased bowl and cover with a kitchen towel or plastic wrap and place it in a warm area and let it rise until it doubled in size. Depending on how warm it is, could take 30 minutes to an hour or longer.
Punch down the dough and divide into 4 equal parts using a knife or dough slicer. Roll each into a log about 6-inch long. Arrange the pieces on a baking sheet and cover with a clean kitchen towel. Leave them to rise for another 10-15 minutes. While waiting, preheat oven 370° F /185°C.
Bake for 15 minutes or until the sides are a slightly brown. Remove from the oven and let cool down. Cut each piece into 4 equal parts, lengthwise.
Place them in a bread box or simply cover with a dry kitchen towel. Leave them at room temperature for a day or two (or longer) to dry out and harden. You may also proceed to the next step without drying them out but adjust for longer baking time.
Preheat oven to 150°C.
Arrange the pieces on a baking sheet lined with parchment paper. Brush a thin layer of softened butter or margarine on each piece on the cut sides. Next, brush them liberally with condensed milk.
Bake for 20-30 minutes or until the edges are slightly golden and condensed milk has become glossy but no longer tacky. Bread should also dry out and become crunchy.
If you are using fresh bread, then you need to bake them longer at low temperature until the bread dries up and hardens. Bake at 100C for about 1 to 2 hours.