Combine all dry ingredients in a stand mixer’s mixing bowl. 3 ¼ c AP unbleached flour, 1 tbsp instant yeast, ½ tsp salt
Meanwhile, whisk milk and egg together in a different small mixing bowl until the egg is well beaten.
1 c whole milk, ½ c sweetened condensed milk, 1 large egg
On low speed, add wet ingredients to the dry mixture (using a stand mixer dough hook). Mix until cohesive dough forms and no dry flour remains, about 1 minute.
Use a rubber spatula to scrape down the sides of the bowl if necessary.
Increase speed to medium-low; add softened butter, one piece at a time. Make sure each piece is fully incorporated before adding the next.
2 oz unsalted butter
Then, mix the dough until it is smooth and elastic and pull completely from the sides of the bowl—approximately 7 to 8 minutes.
Please do not add more flour to the dough because it is intentional for it to be lightly wet.