2 sticks (1/2 pound) unsalted butter, at room temperature
2 cups sugar
4 large eggs, at room temperature
1 cup buttermilk
1 teaspoon pure vanilla extract
Silver dragées, for decorating
Preheat the oven to 350°. Butter and flour two 9-inch cake pans. On a sheet of wax paper, sift the flour, baking powder, baking soda and salt.
In a large bowl, using an electric mixer, beat the butter at medium speed until creamy. Beat in the sugar until fluffy, about 2 minutes. Add the eggs, 1 at a time, beating well between additions. Beat in the dry ingredients at low speed, in 3 additions, alternating with the buttermilk. Beat in the vanilla.
Spoon the batter into the prepared pans and bake in the center of the oven for about 35 minutes, until golden and a cake tester inserted in the centers comes out clean. Let the cakes cool on a rack for 10 minutes. Unmold the cakes and let cool completely on the rack.
Transfer a cake layer to a plate and frost the top generously with icing. Cover with the second cake layer and spread the top and sides with the remaining icing. Decorate with dragées and serve.
Although best when freshly made, the cake can be refrigerated overnight.