In mixer bowl, combine starter, milk, butter, honey, dough enhancer, and 2 cups flour. Mix until smooth. Add remaining flour in 1/4 cup increments until dough starts to pull away from the sides of the bowl. Allow the dough to rest for about 20 minutes. Add salt and knead for 8-9 minutes. If dough is too sticky, add slightly more flour but dough should be soft and slightly tacky, not dry and stiff. Place in greased bowl turning dough to coat top. Cover and allow dough to proof for 5-6 hours or until nearly doubled in size. (I use a Tupperware Thatsa Bowl with lid) Divide dough into 3 ounce pieces. Shape each piece of dough into a ball. Place on a parchment lined cookie sheet. Press dough balls flat with the palm of your hand. Allow buns to rise for 2 hours or until puffy. Beat egg until frothy. Brush over unbaked buns. Sprinkle with toppings of your choice. Bake at 350 degrees for 18-19 minutes. 16 Hamburger Buns