1 cup MINUS 1 Tbsp all purpose flour [stirred, spooned, and leveled to measure]
2 Tbsp cornstarch
1 Tbsp PLUS 1 tsp unsweetened cocoa powder
1/2 tsp baking soda
1/2 tsp salt
3/4 cup PLUS 1 Tbsp sugar
6 Tbsp vegetable or canola oil
2 Tbsp (1/4 stick) unsalted butter, melted and slightly cooled
1/2 cup buttermilk
1/4 cup unsweetened applesauce
1 large egg, room temperature
1 large egg yolk, room temperature
1 1/2 tsp distilled white or apple cider vinegar
1 tsp pure vanilla extract

Cinnamon Vanilla Cream Cheese Frosting
5 cups powdered sugar
1/2 tsp ground cinnamon (optional)
6 Tbsp (3/4 stick) unsalted butter, room temperature
1 1/4 cup (10 oz.) cream cheese, room temperature
1/2 tsp pure vanilla extract