How to Make It
Preheat the oven to 350°. Butter and lightly flour a 10-by-5-inch loaf pan, tapping out any excess flour.
In a medium bowl, whisk the 3 cups of flour with the baking soda and salt. In a large bowl, using a hand mixer, beat the 2 sticks of butter with the granulated sugar and vanilla at medium speed until light and fluffy, about 5 minutes. At low speed, beat in the eggs one at a time until well incorporated. Beat in the sour cream. Beat in the dry ingredients and the buttermilk in 2 alternating additions, scraping down the bowl, just until well combined.
Scrape the batter into the prepared pan and smooth the surface. Bake for about 1 hour and 40 minutes, until golden and a cake tester inserted in the center comes out clean. Transfer the cake to a rack and let cool completely. Dust with confectioners’ sugar and serve.