The Day Before Dye the Eggs
Fill six small bowls with 1 cup (8 fl oz/240 ml) of water. Add 1 teaspoon of vinegar to each bowl and add a few drops of different food coloring to each bowl until you get your desired colors.
Add an egg to each bowl and turn in the colored water for 5-10 minutes, until the eggs take on the color you want.
Transfer to a wire rack to allow the eggs to dry completely, then refrigerate until needed. This can be done up to 2 days in advance.
Make the Sponge
In a medium bowl, combine the flour, yeast and water and cover with plastic wrap. Let sit on the counter overnight.
The Next Day Make the Dough
The next day, using a stand mixer fitted with a dough hook, mix the sponge with all of the dough ingredients: flour, sugar, yeast, salt, butter, eggs, yolk, vanilla extract, orange oil, aniseed and orange zest on low speed for about 10 minutes, until you have a very soft, smooth dough that clears the sides of the bowl but remains stuck to the bottom. If absolutely needed, add a touch more flour, but use as little as possible.
Transfer to an oiled bowl, cover and let rise in a warm place until doubled in size, about 2 hours.
Shaping the Dough
Line a baking sheet with parchment paper.
Divide the dough in half and roll each piece into a 20-inch (50 cm) long log. Twist the logs together and then bring the ends together to form a circle.
Carefully transfer to the prepared baking sheet and lightly cover with plastic wrap. Let rise again until doubled, about 1 hour.
Bake the Bread
Towards the end of the rising time, preheat the oven to 375°F (190°C).
Carefully pull the rope strands apart and nestle the eggs in the wreath, then brush all over with egg wash.
Bake for 15 minutes, then lower the heat to 350°F (180°C) and bake for another 20 minutes. If the bread begins to overbrown, then tent it with foil for the remainder of the bake time. Remove from the oven to cool completely.
Make the Glaze
In a small bowl, combine the powdered sugar and 2 tablespoons of milk. If you would like a thinner glaze, add a little more orange juice, a few drops at a time, until you get the consistency you want. Drizzle the bread with the glaze and add the sprinkles on top. Let the glaze dry before serving.
This is best the day it is made but you can store the leftovers in an airtight container at room temperature for up to 2 days. Note we do not recommend eating the eggs.