1/4 cup
                        (57 grams) unsalted butter, cold, cubed, plus more for the pan
                                        
                        
                        3 cups
                        (384 grams) all-purpose flour, plus more for the pan
                                        
                        
                        2 cups
                        (400 grams) granulated sugar
                                        
                        
                        1 tablespoon
                        baking powder
                                        
                        
                        1 1/2 teaspoons
                        kosher salt
                                        
                        
                        1/4 teaspoon
                        ground turmeric
                                        
                        
                        3/4 cup
                        (145 grams) canola oil
                                        
                        
                        4 1/2 teaspoons
                        vanilla extract
                                        
                        
                        2
                        large eggs
                                        
                        
                        2
                        large egg yolks
                                        
                        
                        2 cups
                        (467 grams) buttermilk, room temperature
                                        
                        
                        3/4 cup
                        (170 grams) unsalted butter, melted and cooled slightly
                                        
                        
                        1 cup
                        (85 grams) natural cocoa powder
                                        
                        
                        1 1/2 teaspoons
                        vanilla extract
                                        
                        
                        3/4 teaspoon
                        kosher salt
                                        
                        
                        4 1/2 cups
                        (513 grams) powdered sugar
                                        
                        
                        1/2 cup
                        strong, cold coffee, plus more as needed