Mix together the warm water and the yeast in a small bowl until it starts bubbling slightly. About one minute.
Put eight eggs (uncracked) into a large bowl. Cover with hot water and set aside until they are warm.
In a medium sauce pan, heat up the milk, salt, sugar and vanilla bean seeds and pod (after you have removed the seeds) over low to medium heat. Leave the mixture to melt and dissolve, about 5 minutes.
Add 1/4 of a cup of flour into the yeast mixture. Add a little of the 1/4 cup of flour at a time. Just feed the yeast. Make a very soft, wet dough. Set aside or in a proofing oven until it doubles in size. About 10 minutes.
Put the flour into a mixing bowl. Make a well in the flour that is in the bowl.
Crack the now warm eggs into the well of the flour that is in the mixing bowl. Then add the warm vanilla bean mixture into the flour well also. And finally, add the yeast that has doubled in size to the flour well. Place with a wire whisk into your stand mixer and mix until it is smooth on a medium speed.
Once the dough is smooth, place the butter, cut into 1/2" slices, right on top of the dough. Place plastic wrap on top, then place into a proofing oven (or an oven at 80-90 degrees) and let it rise for 30-40 minutes or until it doubles in size.
Once the dough has doubled in size, place back onto the stand mixer (removing the plastic wrap) and mix together the dough and butter using the paddle until the butter is full incorporated.
Using savarin baking pans (circular and smooth), any size that you prefer (small, medium or large), place the dough into a pastry bag. Place just enough dough to fill up a third of the cake pan as it will rise.
Proof the cake pans with the dough for 20 minutes until twice in size.
Preheat the oven to 350 degrees. Once at temperature, place the cake pans with the risen dough into the oven to bake for 20-25 minutes or until they are lightly brown. The top that you can see will be less brown than the rest of the cake, so do not base the brown you see as the brown you want.
Remove the cakes from the pans by simply flipping them over. Poke the bottoms (flat side) with a fork so that the liqueur mixture can absorb more easily into the cake.