Instructions: Place the mixer bowl and whisk beater in the freezer. Measure the sugar into a zip-top plastic bag, seal and place in the freezer to chill for about 20 minutes.

Place a shelf at the top of the lower third of the oven and preheat to 350 degrees.

Grease a 9- by 2-inch round cake pan by spraying with nonstick cooking spray or by rubbing the pan with shortening, shaking the pan with 1 tablespoon flour, and shaking out the excess. Insert a 9-inch parchment or waxed paper circle in the pan and lightly spray or grease and flour.

Sift the flour, baking powder and salt onto a sheet of waxed paper. Resift at least once more onto another piece of waxed paper. Measure the buttermilk in a glass measuring cup and add the vanilla.

Cream the butter on medium speed in a mixer with the whisk until light in color, about 3 minutes. Add the sugar in a steady stream with the mixer running. Continue beating the butter-sugar mixture for 3 to 4 minutes, scraping down the sides of the bowl once. Add the eggs and yolks one at a time, beating on medium speed for about 30 seconds after each addition. Continue to beat until the mixture is light and airy looking, another 1 to 2 minutes.

Remove the bowl from the mixer and stir in the oil. Fold in half of the flour mixture with a large rubber spatula. Scrape down the sides of the bowl, then fold in half of the buttermilk-vanilla mixture. Fold in the remaining flour and scrape down, then the remaining buttermilk-vanilla mixture.

Pour the batter into the prepared pan. Smooth the batter with the rubber spatula, leaving the edges a breath higher than the center. Bake until a toothpick or cake tester inserted an inch from the center comes out clean, about 35 minutes. The sides should just begin to pull away from the pan when you place the cake on the rack to cool.

Let the cake cool in the pan for 10 to 20 minutes. Tap the sides of the pan on the counter to loosen the cake or run a small spatula around the edge. Spray a cooling rack lightly with nonstick spray and invert the cake onto it. Peel off the parchment liner, then replace the liner on the cake with the sticky side up. Invert back onto the original cooling rack so that the cake is now right side up. Cool completely before storing or icing.

Comments: Walnut, hazelnut or almond oil is good to use if you would like a subtle flavor note. Make sure the oil is not off tasting since nut oils turn rancid faster than others.

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