In the bowl of a mixer, over medium low speed, beat the butter until soft. Add the sugar and beat until combined and fluffy. Add one egg at a time. Once eggs are incorporated, add the milk and yeast mixture. Then adding ½ cup at a time, add the rest of the flour (3 ½ cups). Stir in the orange blossom water if using and if not, add plain water. Also add the anise seeds and a pinch of salt. The dough will look wet, runny and sticky, but continue beating anywhere from 7 to 10 minutes, until all the dough comes off the sides of the mixing bowl. It will be elastic and sticky, but it will hold itself together.
Butter a large mixing bowl that can hold the dough, and will be able to hold it as it doubles or triples its volume. Place the dough in the bowl, cover it with a cloth or clean kitchen towel and leave it in the warmest area of your kitchen, that is draft free, making sure that it is not next to a window or door that gets opened. Leave it to rest and puff up anywhere from 2 to 3 hours, until it doubles its volume at least.
Punch the dough with your fist, flip it over, cover with plastic wrap and place in the refrigerator over night. The next day, remove the plastic wrap, place a cloth or kitchen towel on top and let it to come to room temperature.
Take off a third of the dough to make the bread decorations: make a 1 to 2-inch ball and use the rest to make 2 ropes. They need not be smooth nor perfect, as the dough is quite sticky, and no need to worry they will look beautiful once the bread is baked (and covered with sugar).
Butter a baking sheet or a bread or pizza stone, and make a ball with the rest of the dough. Place it in the center of the baking sheet and flatten it a bit on top. Place the dough ropes making a criss-cross -Mexican bakers usually shape the ropes to resemble bones, having thicker and thinner parts- and the ball on the top, right where they cross. Cover the bread with a cloth or kitchen towel, and let it rise and puff up again, for 1 to 2 hours.
Preheat the oven to 350. Bake the bread for for about 35 minutes. Halfway through baking, after about 20 minutes, cover the loaf with parchment paper or aluminum foil to prevent it from browning too much.
When they are ready, they sound "huecas", or hollow, if you hit the bottom of the bread.
Melt the butter and brush all over the bread. Sprinkle sugar all over until completely covered.