Sift flour through a fine sieve mesh into a mixing bowl.
Add the rest of dry ingredients into the bowl.
Using a dough hook and your stand mixer, on slow speed, add egg, milk,and condensed milk to dry mixture and mix until a sticky dough forms, about 1 minute.(Use rubber spatula to scrape down sides of the bowl if needed)
Increase speed to medium-low, add butter, one piece at a time, and mix until butter is fully mixed in.
Continue to mix the dough until it is smooth and elastic, about 2 minutes. Make sure there isn't any dry flour on the bottom of the mixing bowl.
Move the dough to a lightly greased large mixing bowl and use your hand to knead the dough to form a smooth round ball.
Turn the smooth dough seam side down. Cover the bowl tightly with plastic wrap and let the dough rise until it has doubled in size. This takes about 1.5 to 2 hours.
Grease your baking pan with butter.When the dough has risen, punch it down. Then transfer it to a lightly-floured counter or baking board.
Divide the dough into 9 equal pieces.
Working with 1 piece of dough at a time (cover the rest with plastic wrap) to form each small roll. Use your fingers to stretch the dough, pinching the edges together at the bottom and rolling it between your palms to form a smooth ball.
Then transfer the dough ball,, seam side down, to the already greased baking pan.
Repeat for the remaining dough balls, and arrange them in the baking pan.
Lightly cover them with plastic wrap and let them rise again until almost double in size. Make sure they don’t rise above the rim of the pan.
Preheat oven to 340F.
Gently brush dinner rolls with egg wash mixture and bake from 25 to 30 minutes, rotating the pan half way.
Your condensed milk dinner rolls should have a deep or bright golden-brown crust, depends on your preferences.
Take the baking pan out and let the rolls cool down for 5 minutes at room temperature. Lightly brush a layer of condensed milk glaze on top of the rolls when they are still warm.
Then let them cool down for another 30 minutes to an hour before serving. You can serve these rolls warm or at room temperature.