Dissolve yeast in warm water in large bowl.
Add milk, sugar, butter, salt, and egg.
Stir in 2 cups of the flour and beat until smooth.
Add enough flour until dough easy to handle and forms a ball.
Turn onto a lightly floured surface and knead until smooth and elastic. This should take about 5 minutes.
Place dough in a large greased bowl, then turn greased side up.
Cover, place in a warm place, and let rise until double, about 1 1/2 hours. You’ll know the dough is ready if an indentation remains after you press into it.
While the dough is rising, prepare the topping. See below.
Punch conchas dough down and divide into 12 equal pieces. Shape them into balls and place on greased cookie sheet.