This timeless frosted vanilla cake is finished with lemon zest tossed in granulated sugar for a sweet, citrusy crunch.
Preheat oven to 350 degrees. Lightly butter a 9-by-13-inch baking pan; dust with flour. Whisk together flour, baking powder, baking soda, and salt.
Beat butter with 1 cup sugar on medium speed in a mixer fitted with the paddle attachment until light and fluffy, 5 minutes. Add eggs, one at a time, beating until combined after each addition and scraping down sides of bowl as needed. Beat in vanilla. Reduce speed to low and add flour mixture in two batches, alternating with buttermilk and beginning and ending with flour.
Transfer batter to prepared pan, smoothing top with an offset spatula. Bake, rotating pan halfway through, until cake is golden and puffed and a tester inserted in center comes out clean, 22 to 25 minutes. Let cake cool completely in pan on a wire rack.
Combine lemon zest and remaining 1 teaspoon sugar. Use an offset spatula to spread cake with frosting. Sprinkle with lemon sugar. Serve, with blueberries.