Preheat the oven to 385 degrees F.
Butter, then flour, a 12-cup muffin pan, and set aside.
In a small mixing bowl, stir together the yeast and warm water until the yeast dissolves. Add 1/8 cup flour, stirring until a paste is formed. Set aside for 10 minutes.
In a mixing bowl, beat the butter and sugar together with an electric mixer for about 5 to 6 minutes, until a light ribbon is formed. Remove the beaters and clean all of the butter mixture off the beaters into the bowl. Place a dough hook attachment on the mixer and add the yeast mixture, the remaining flour, the salt, the eggs and yolks and mix well, about 8 to 9 minutes, until the dough pulls away from the sides of the bowl. Remove the dough from the mixing bowl and divide it into 12 equal portions. Place each portion into a cup of the prepared muffin pan, cover with a towel and allow to stand for 1 hour, to double in bulk.
Place the cakes in the oven and bake for 20 to 25 minutes, until cooked through or when a toothpick entered at the center exits clean. Remove and allow to cool on a cake rack for 20 minutes. Remove the cakes from the pan and place them on a sheet tray.
In a small saucepan, heat the water and sugar to boiling and stir to dissolve the sugar. Lower heat to a very high simmer and cook 15 minutes to form a simple syrup. Remove from heat, add rum, stir to mix and allow to cool 5 minutes.
Poke the tops of the cakes with a popsicle stick to form 8 to 10 slender holes. Spoon the rum syrup over the cakes and into the holes, and repeat twice with the syrup that drains out of the bottom. Serve with unsweetened whipped cream.
All recipes copyright 2000, Mario Batali. All Rights Reserved