Serves: Serves 6 to 8
- ¾ cup (5¼ ounces) sugar
- 1 vanilla bean
- 1½ sticks (6 ounces) unsalted butter, softened (65° to 68°F)
- 3 large eggs, at room temperature
- 1 tablespoon pure vanilla extract
- 2 cups (7 ounces) sifted cake flour
- ½ teaspoon baking powder
- ¼ teaspoon salt
- 1/3 cup (3 ounces) sour cream, at room temperature
Preheat the oven to 350°F and position an oven rack in the center. Lightly coat the pan with butter, oil, or high-heat canola-oil spray and fit it with parchment paper to extend up both long sides to the top of the pan.
Cream the butter and sugar: Place the sugar in the bowl of the stand mixer. You can also use a hand mixer and a medium bowl, although you may need to beat the mixture a little longer for each step to achieve the same results. Use a paring knife to split the vanilla bean lengthwise, then turn the knife over and use the dull edge to scrape the seeds into the sugar. (Save the vanilla pod for another use.) Blend on low speed until the seeds are evenly dispersed. Add the butter and beat on medium-high until the mixture is very light-almost white-in color, 4 to 5 minutes. Scrape down the bowl with the spatula.
Add the eggs: Beat the eggs in the small bowl. With the mixer running on medium speed, add the eggs to the butter mixture about 1 tablespoon at a time, allowing each addition to completely blend in before adding the next. About halfway through, turn off the mixer and scrape down the bowl, then continue adding the eggs. Mix in the vanilla extract. Scrape down the bowl again.
Add dry and wet ingredients alternately: With the fine-mesh strainer, sift the cake flour, baking powder, and salt into the medium bowl and whisk together. With the mixer on the lowest speed, add the flour mixture and sour cream alternately, beginning with one-third of the flour mixture and half the sour cream; repeat, then finish with the flour mixture. Scrape down the bowl and finish blending the batter by hand.
Bake the cake: Scrape the batter into the prepared pan and smooth the top. Bake for 45 to 55 minutes, until firm to the touch and a toothpick inserted into the center comes out clean. Transfer to a rack to cool completely. When cool, remove from the pan, peel off the parchment paper, and serve.
Storing: The cake can be made several days ahead and kept at room temperature, wrapped in plastic wrap. Or double-wrap, put in a resealable plastic freezer bag, and freeze for up to 8 weeks.