Combine the yeast, salt and sugar in the bowl of a stand mixer. Whisk in 2 eggs.
In a small saucepan over medium-low heat, warm the milk and butter to 120F-130F degrees. Pour the warmed milk into the yeast mixture.
Stir 2 cups of flour and lemon zest into the yeast mixture. Use the dough hook attachment to knead the dough for 2 minutes. Scrape down the sides of the bowl to ensure that everything is combined.
With the motor running, slowly add the remaining 2 cups of flour. Knead for 12-15 minutes, until the dough sticks to the hook and not the bowl. Add more flour by the spoonful if the dough looks too sticky.
Shape the dough into a ball and place it on a parchment lined baking sheet. Cover loosely with a dish towel. Rest for 10 minutes.
Preheat the oven to 200F degrees.
Divide the dough into 3 ropes approximately 24" long. Braid the dough. Then, attach the two ends together so that the dough forms a ring.
If desired, place dyed hard-boiled eggs on top of the dough. Do not press down (they will sink as the bread bakes).
Cover the dough loosely with a dish towel. Turn off the oven and place the dough into the warm oven. Let rise 45-50 minutes. Remove from oven.
Preheat oven to 350F degrees.
Beat the remaining egg with 1 tsp. of water. Brush the dough with egg wash. Top with colored sprinkles, if desired.
Bake 25 minutes, until golden brown. Cool completely before transferring to a wire rack.