In a microwave bowl, heat the milk for 45 seconds on high to 105-110 degrees F. A drop of milk at this temperature will feel very warm on the inside of your wrist. Or check with a food thermometer. Pour the milk into a mixing bowl and sprinkle on the yeast. (See "Proofing the Yeast" note below.)
Then add the sugar, eggs, and butter. Whisk together. Then add the flour and salt and stir until a stiff dough forms.
Using a dough hook, knead for 7 to 8 minutes. The dough should pull away from the bowl as it kneads. If the dough is too sticky and sticks to the bowl, add 1-2 tablespoons of flour and continue kneading.
After kneading, move the dough to a well-oiled bowl and cover with plastic. Let rise for 1½ hours or until doubled in size.
Turn the dough out onto a floured surface. Roll into a rectangular size approximately 16 x 10 inches.
Spread the butter onto the dough.
Whisk together the sugar, flour, and orange zest and sprinkle over the butter.
Carefully roll up the 16-inch side of the dough into a tight roll. Then use a string or dental floss to cut off the uneven ends of the roll. (If any sugar falls out of the rolls when you cut them, tuck it back in as well as you can.)
Then cut 15 evenly-sized pieces and place them in an 11-inch round pan or equivalent size. Do not tightly pack the rolls so they have room to rise.
Cover with plastic and let rise in a warm place for 45 minutes.
Preheat oven to 350 degrees F and bake uncovered buns for 20-25 minutes or until lightly browned and no longer doughy in the center. (Because oven temperatures vary, you may need to bake them up to 35 minutes.) Let the rolls cool for a few minutes before adding the icing.