"Making this year-round...."
Cooking spray
lukewarm milk
plus 1 tsp. granulated sugar, divided
or 1 (0.25-oz.) package active dry yeast
all-purpose flour, plus more for surface
kosher salt
large eggs
(1 stick) butter, softened and cut into cubes
Egg wash, for brushing
Sprinkles, for topping
large eggs
boiling water, divided
distilled white vinegar, divided
Food coloring