Mmmmm yummy. These are so awesome.
Replacing cake flour with all-purpose flour removes the tender, fine crumb that defines a true New York style bakery cake. This formulation relies on low-protein flour to keep the dense batter from developing excess gluten structure. The hallmark of the style is an extraordinarily deep layer of buttery streusel topping, often equal in weight to the cake base itself. Bakers frequently err by melting the butter for the crumb completely past the cooling stage, which dissolves the sugar instead of creating coarse, pea-sized clumps. Mixing the base requires adding chilled butter gradually to dry ingredients until a sandy consistency forms, rather than creaming butter and sugar together in the traditional cake method. Operating the stand mixer on medium-high for at least one full minute after adding the buttermilk, vanilla, and eggs builds the necessary emulsion in a batter that resembles stiff frosting. Placing the baking pan on the upper-middle oven rack at 325 degrees Fahrenheit prevents the bottom and heavy sugar topping from scorching before the center sets. Allowing the baked cake to rest undisturbed in the pan for thirty minutes firms the crumb sufficiently for safe extraction via the parchment sling.