Cinnamon Babka

Name: Cinnamon Babka
Prep time: 3 h
Cook time: 2 h
Total time: 5 h
Cuisine: Middle Eastern
Ingredients: 2 1/4 teaspoons active dry yeast ((1 packet)); 3 tablespoons granulated sugar, (plus 1 tsp for activating yeast); 2/3 cup whole milk, (warmed to 110 degrees F, plus 1 additional tbsp for egg wash); 5 tablespoons unsalted butter, (room temperature); 1 1/2 tablespoons vegetable oil ((I use canola or grapeseed)); 1 1/2 teaspoons vanilla extract; 4 egg yolks ((reserve 1 egg white for egg wash and 1 egg white for cinnamon filling)); 2 1/2 - 3 1/4 cups all purpose flour ((flour amount detailed in instructions below)); 1 teaspoon kosher salt; 1 cup dark brown sugar; 1/4 cup all purpose flour; 3 teaspoons ground cinnamon; 1/2 teaspoon kosher salt; 2 tablespoons unsalted butter, (melted); 1 egg white; 1/4 cup dark brown sugar; 2 tablespoons unsalted butter, (chilled and cut into small pieces); 1/4 teaspoon salt