In the bowl of a stand-up mixer, whisk together the flour, salt, zest, and sugar, make a well in the center and add the milk and yeast, mix together with a fork.
Then add the slightly beaten eggs. With the dough hook attachment knead for approximately 1 minute just to combine.
Cover the bowl and let rise 2 hours, every 30 minutes fold both ends into the middle (repeating 4 times).
When the time has passed add the butter a little at a time, on medium high speed with the dough hook, knead just to combine all the butter, then let the dough rest 10 minutes.
Knead again for 5-6 minutes until smooth and the dough does not stick to the sides of the bowl.
Place the dough in a lightly greased bowl, cover and refrigerate for 2 hours.
Move the dough to a lightly floured flat surface. Divide the dough into 2 parts. Divide each piece of dough in half and roll each part into 2 ropes (10-12 inches), join 2 ropes at the top and twist the ends one over the other, join the ends to form a wreath (circle)repeat with the remaining ropes.
Place the wreaths on a parchment paper lined cookie sheet, cover and let rise in a warm draft free area for 2 hours or doubled in bulk.
Preheat the oven to 375 degrees.
First, brush the wreathes with egg wash and then secondly, place the dyed hardboiled egg in the center of the wreath. Do not push the eggs into the dough, the eggs will nestle into the dough when baking. If desired add a touch of sprinkles for extra color. Bake for approximately 10-15 minutes or until golden, or when tapped on the bottom and there is a hollow sound.
Immediately move the baked buns to a wire rack to cool before serving.