Crumb Cake

Ingredients

• 1 1/2 cups cake flour
• 2/3 cup packed dark brown sugar
• 2/3 cup granulated sugar
• 1 1/2 teaspoons ground cinnamon
• 1/4 teaspoon kosher salt
• 8 tablespoons (1 stick) unsalted butter, melted and cooled
• Cooking spray
• 3 cups cake flour
• 1 1/2 cups granulated sugar
• 1 1/2 teaspoons baking soda
• 1 1/2 teaspoons baking powder
• 1 1/2 cups sour cream, at room temperature
• 1/4 cup whole milk, at room temperature
• 3 large eggs, at room temperature
• 2 large egg yolks, at room temperature
• 12 tablespoons (1 1/2 sticks) unsalted butter, melted and cooled
• 1 tablespoon vanilla extract
• 3/4 teaspoon kosher salt
• Powdered sugar, for dusting (optional)