Pumpkin Cake

Ingredients

• For the cake:
• 8 ounces unsalted butter, softened to about 70°F
• 14 ounces plain or toasted sugar
• 1 tablespoon baking powder
• 1 tablespoon potato flour, such as Bob's Red Mill
• 1 teaspoon Diamond Crystal kosher salt; for table salt, use about half as much by volume or the same weight
• 2 teaspoons ground ginger
• 2 teaspoons ground cinnamon
• 1/2 teaspoon ground cloves
• 5 ounces organic egg yolk, from about 8 large eggs, brought to about 70°F
• 1/2 ounce vanilla extract
• 3 ounces milk, brought to about 70°F/21°C, any percentage will do
• 12 ounces pumpkin or butternut squash purée, canned or homemade
• 13 1/2 ounces bleached cake flour, such as Swans Down
• To Finish:
• 1 recipe Cream Cheese Buttercream
• Ground cinnamon, to taste, optional
• 5 ounces toasted pecan pieces, optional

Directions

1. Start with the Cream Cheese Buttercream so the pauses line up nicely once the cake is baking and cooling. Move an oven rack to the lower-middle spot, then heat the oven to 350 degrees F (180 degrees C). Give 2 8-inch anodized aluminum cake pans a light coating of grease, and fit parchment into the bottoms.
2. In a stand mixer bowl with the paddle attached, put the butter, sugar, baking powder, potato flour, salt, ginger, cinnamon, and cloves. Begin on low just until everything is dampened, then switch to medium and beat until the mixture turns pale, plush, and airy, about 8 minutes; stop midway to clean down both the bowl and the paddle. Keep the mixer going while you drop in the egg yolks 1 at a time, then pour in the vanilla, and be gentle here so you do not take the batter too far.
3. While that is happening, whisk the milk with the pumpkin purée until no streaks remain. Turn the mixer down to low, dust in a third of the cake flour, and then add a third of the pumpkin-milk blend. Continue switching back and forth, letting each pour or sprinkle mostly disappear before the next goes in. When the batter looks even, reach in with a flexible spatula and sweep up from the bottom to catch anything hiding there. Portion the batter into the pans, aiming for just about 27 ounces (756g) in each.
4. Bake the layers until they have climbed nicely and feel set when you press them, about 35 minutes, or until they reach 200 degrees F (93 degrees C). If you check the middle with a toothpick, expect a few crumbs rather than a clean skewer. Because these cakes are thick, let them cool until every bit of heat is gone, about 2 hours. Slide a butter knife around the sides, turn the cakes out onto a wire rack, lift away the parchment, and flip them back upright. If wrapped in plastic, they may sit at room temperature for a few hours.
5. Trim the cakes level with a serrated knife, and keep the trimmings for nibbling or crumbling into freshly churned Buttermilk Ice Cream. Set 1 layer on a sturdy cast iron turntable; if you want to use a waxed cardboard cake round, slip it underneath first and hold it to the turntable with a damp scrap of paper towel. Add exactly 1 cup buttercream and smooth it with an offset spatula until it runs evenly from edge to edge. Put the second cake layer on top and repeat that same buttercream layer, then spread another cup of buttercream over the sides, getting it as smooth as you reasonably can. Refrigerate until the buttercream sets hard, about 30 minutes.
6. Beat the remaining buttercream again to bring it back to a creamy texture, then decorate the cold cake however you like. If you are using them, dust with cinnamon and add the toasted pecans. Before slicing, let the cake come back to a cool room temperature. Use a chef's knife for serving, and seal any cut sides with leftover buttercream so the cake stays moist. Kept beneath a cake dome, it will hold at room temperature for 3 days.