Babka (Chocolate)

Bahan-bahan (18 porsi)

• 3/4 cup milk (warm, 105–115°F)
• 2 teaspoons sugar
• 4 teaspoons active dry yeast
• 1/2 cup sugar
• 1/2 cup all-purpose flour
• 2 large eggs
• 1 large egg yolk
• 1 teaspoon pure vanilla extract
• 3/4 teaspoon salt
• 2 & 3/4 cups flour (plus more for dusting)
• 10 tablespoons unsalted butter (1 & 1/4 sticks, cut into pieces and softened)
• 1 large egg yolk
• 1 tablespoon cream
• 5 tablespoons butter (divided and well softened)
• 1 & 1/2 10-oz bags bittersweet baking chips (60% cacao, divided)
• 1/3 cup sugar (divided)