Let the dough rise for an hour or two until it doubles in size.
Meanwhile, take the yeast and mix it with 2 tbsp of warm milk, 2 tbsp of sugar and 1 tbsp of flour and mix it well. Let it rest, if the yeast is fresh you will see the mixture rise. Leave it for about ten minutes. In a big bowl add the flour and if you're using vanilla powder add it to the flour otherwise add it to the milk mixture. Add 5 egg yolks (the whites will be used for the pecan cream) to the milk mixture and mix well. Next I usually use my kitchen aid mixer with the dough or paddle attachment. Add the flour to the bowl of the mixer, the milk mixture and the yeast mixture as well. Mix well for a few minutes. In the old days you'd have to knead this by hand for at least half hour. The more it mixes the fluffier the dough will be. Add the raisins and mix well.
In a sauce pan add the sugar, milk, butter and lemon zest then warm it up. Do not boil it, it just needs to be hot.