Created by KittenCal on November 13, 2016
Step 1: Preheat the oven to 325°F (175°C). Butter an 13x9- inch glass cake pan or divide the batter between two 8-inch glass pans.
Step 2: In a bowl using an electric mixer, cream together the butter and sugar in a large bowl until light and fluffy (there should be no sugar granules remaining). Beat in the 2 whole eggs and one yolk, one at a time. Beat in the lemon juice from 1 whole lemon plus the zest from 1 lemon. Beat in the sour cream until combined.
Step 3: In a bowl, combine the flour and the baking powder. Add to the creamed mixture beating on lowest speed until just combined (batter will be quite thick).
Step 4: Spread in the pan. Bake for 25-30 minutes, or until the center springs back when pressed.
Step 5: Cool then dust with powdered sugar if desired.