Domingo Chocolate Cake
["1/4 c. plus 3 Tbsp. unsweetened cocoa", "2/3 c. sour cream", "2 large eggs", "1/2 tsp. vanilla", "1 1/2 c. plus 1 Tbsp. sifted cake flour", "1 c. sugar", "3/4 tsp. baking powder", "1/4 tsp. baking soda", "1/2 tsp. salt", "14 Tbsp. unsalted butter"]
["Preheat the oven to 350\u00b0.", "In a medium bowl, whisk together the cocoa, sour cream, eggs and vanilla until smooth."]
["unsweetened cocoa", "sour cream", "eggs", "vanilla", "cake flour", "sugar", "baking powder", "baking soda", "salt", "unsalted butter"]