• 3 cups sifted cake flour (not self-rising)
• 1 tsp. baking powder
• 1/2 tsp. salt
• 1/2 tsp. baking soda
• 1 1/2 cups (3 sticks) unsalted butter , room temperature
• 2 cups sugar
• 5 large eggs
• 2 tsp. pure vanilla extract
• 1 cup buttermilk  

Adjust rack to center of oven and heat to 325°. Line jumbo muffin pans with baking cups; set aside. In a medium bowl, sift together flour, baking powder, salt and baking soda; set aside.

In the bowl of a heavy-duty electric mixer fitted with the paddle attachment, beat the butter and sugar on medium speed until light and fluffy, about 3 to 5 minutes. With mixer running, add eggs and vanilla extract; beat until combined.

With mixer on low speed, add 1 cup reserved flour mixture; mix until combined. Add 1/2 cup buttermilk; combine. Alternate adding flour mixture and buttermilk, ending with flour, until all has been incorporated.

Divide batter evenly between baking cups. Bake until light golden brown and a cake tester inserted into middle comes out clean, 25 to 30 minutes. Rotate pans halfway through baking.  Transfer pans to a wire rack to cool.