Dissolve the yeast in 1/2 cup of warm milk and 4 tbs. flour. Work into dough. Place dough in a bowl, cover, and let it stand in a warm place for 30 mins. or until it doubles in size.
Make a fontana on a pastry board with the remaining flour, a pinch of salt, the eggs, sugar, butter and fermented dough. Soak the raisins in lukewarm water, then squeeze out the excess water and add them to the dough. Pour the mix in a large, buttered, sugar-dusted ring mold and let rise again, in a warm place, until it doubles in size (it should take approx. one hour). Bake at 375ºF for 45 mins.
Prepare a syrup by dissolving the sugar in the water, over a low flame. Add the rum. Unmold the babà while still warm. Soak with the rum syrup and serve.
Note:
Small babà are made the same way, only the dough is divided and baked in smaller molds.
