Preheat oven to 350° (325° for convection oven). Coat medium-large sized cake pan with nonstick spray. Coat pan with white sugar (optional step).
Whisk dry ingredients in a medium bowl. Set aside.
Using an electric mixer on medium speed, whip butter. Add sugar while mixing until light and fluffy, about 2 minutes.
Add eggs one at a time, mixing well to incorporate after each addition.
Increase speed to medium-high and beat until mixture is light and fluffy, about 2-3 minutes.
Reduce speed to a lower speed and add lemon zest, juice and vanilla.
In 2-3 additions, add flour mixture while continuing to beat on low. Scrape bowl as needed. Do not overmix.
Pour batter into prepared cake pan.
Bake cake until golden brown and beginning to pull away from sides of pan, 55-65 minutes (or just 25-35 minutes in a convection oven), or until top is golden brown and a tester inserted into the center comes out clean.
Transfer to a wire rack and let cake cool in pan for 15-20 minutes. Invert cake onto rack; remove pan and let cool completely.
Sprinkle with powdered sugar.
After cutting a generous slice, pour a drizzle of the Elderberry Sauce (recipe below) over the top and enjoy!