Ingredients

For the Sponge

• 1 cup milk
• 1/3 cup all-purpose flour
• 2 teaspoons sugar
• 1/2 cup lukewarm water
• 3 (1/4-ounce) packages active dry yeast

For the Dough

• 10 large egg yolks, room temperature
• 2 large eggs, room temperature
• 1 teaspoon salt
• 1 cup sugar
• 8 ounces (1 cup) unsalted butter, melted
• 2 teaspoons pure vanilla extract
• 1 tablespoon lemon zest, grated
• 6 cups all-purpose flour
• 1 cup raisins, light or dark, optional
• 1 large egg, room temperature
• 2 tablespoons milk, or water, room temperature

Instructions

Sponge

1. Scald the milk and cool it to 110 F.
2. Place 1/3 cup flour in a medium bowl and pour the cooled scalded milk over, beating until smooth. Set aside.
3. In a measuring cup or small bowl, dissolve 2 teaspoons sugar in lukewarm water and stir in the yeast.
4. Transfer the yeast mixture to the milk-flour paste, mixing well.
5. Cover with plastic wrap and let rise until light and bubbly.

Dough

1. In a large bowl or stand mixer, beat the egg yolks, whole eggs, and salt.
2. Add 1 cup sugar and continue beating until light.
3. Beat in the butter, vanilla, and lemon zest.
4. Add the sponge to this mixture and mix well.
5. Add 6 cups flour and knead 7 minutes by machine or 10 minutes by hand.
6. Knead in the optional raisins.
7. Cover with greased plastic wrap and let rise until doubled.
8. Punch down dough, knead a few times, and let it rise again.
9. Grease 3 babka cylinders or food-grade coffee tins and fill each pan 1/3 full.
10. Cover with greased plastic wrap and let rise until tripled.
11. Brush tops with 1 large egg beaten with 2 tablespoons of milk or water.
12. Heat oven to 375 F.
13. Bake babkas 10 minutes.
14. Then lower temperature to 325 F and bake 30 minutes.
15. Then lower temperature to 275 F and bake 15 to 20 minutes longer. Cover tops with aluminum foil, if they are browning too quickly.
16. Remove from the oven and let stand in the pan for 10 minutes.
17. Turn loaves out of the pan, running a knife around them, if necessary, and cool completely on a wire rack.
18. If desired, the cooled loaves can be iced with a simple confectioners' sugar glaze, letting it drip down the sides for a decorative effect.