Instructions

Making the Dough (25 minutes + 1 hour proving)

1. Warm the milk in a small saucepan until it reaches 115 F.
2. Pour the bread flour into a large mixing bowl, add the salt and yeast on opposite sides of the bowl, and stir in each one with your finger.  Blend in the sugar.
3. Dump in the softened butter, egg, and half of the warm milk.  Mix with your hand until the dough begins to come together, then trickle in the remaining milk as needed to create a soft, slightly sticky dough.
4. Turn out onto a lightly floured surface and knead for 10-15 minutes, until the dough is soft, smooth, and has a glossy sheen on its surface.  Check to see if the dough is kneaded enough by breaking off a lump of dough and stretching it between the thumb and forefinger of each hand to form a windowpane.  The dough should stretch until it’s translucent without breaking; if not, knead for a minute longer and check again.
5. Shape the dough into a ball, place in a buttered bowl, and tightly cover with plastic wrap.  Set aside in a warm place to prove until doubled in size, about 1 hour.

Shaping the Babka (25 minutes + 1 hour proving)

1. While the dough is proving, measure out the pesto.  Drain off any excess oil, then pour the pesto into a mesh sieve and push out as much oil as you can with the back of a spoon.  You should have 3/4 cup (188g) of drained and squeezed pesto.
2. Turn out the proved dough onto a lightly floured surface and punch it down all over to knock out gas pockets.
3. Roll it out to a rectangle 9 inches wide and 20 inches long, lifting the dough occasionally to relax the gluten.  If the dough is shrinking back a lot when you roll it out, let the dough rest for a few minutes, then try again.
4. Spread the pesto evenly over the bread, getting within an inch of the edge.
5. Roll up the bread tightly from a short end, then pinch all the seams and ends to seal.  Slice the log of dough in half lengthwise, then twist the two lengths together, keeping the filling side up as you twist.
6. Place the babka in a lightly buttered loaf pan and put it inside of a clean garbage bag.  Inflate the bag and tuck the ends under the pan to seal.  Set aside in a warm place to prove until the dough has crowned about an inch over the top of the pan and springs back quickly when gently prodded with a fingertip.
7. About 10 minutes before the babka is done proving, preheat the oven to 300 F.

Baking the Babka (55 minutes + cooling)

1. Bake the babka at 300 F for 35 minutes, then check and cover it with aluminum foil if it’s getting too dark.  Bake for another 20-25 minutes, until the center of the loaf has an internal temperature of 190 F.
2. Let the babka cool for 10 minutes in the pan, then remove and let it cool completely on a wire rack before slicing and serving.