Crumb Cake

Name: Crumb Cake
Prep time: 25 min
Cook time: 45 min
Total time: 1 h 10 min
Cuisine: American
Ingredients: 1 ¾ cup all-purpose flour; 1 cup granulated sugar; ⅓ cup light brown sugar (firmly packed ); ¾ teaspoon baking powder; ½ teaspoon table salt; ¼ teaspoon baking soda; 1/2 cup unsalted butter (softened and cut into 8 pieces ); 1 cup sour cream; 1 large egg + 1 large egg yolk; 1 ½ teaspoons vanilla extract; 1 ⅔ cup all-purpose flour; ⅔ cup light or dark brown sugar (firmly packed); ½ cup granulated sugar; 1 teaspoon ground cinnamon (optional but recommended); ¼ teaspoon table salt (heaping); ½ cup unsalted butter (melted )