• Preheat oven to 350°F.
• Spray a 12x17 inch rimmed baking sheet with nonstick baking spray and line with parchment paper. Grease the parchment paper with butter. Set aside.
• In a medium bowl, beat egg whites on med-high until soft peaks form (1 to 2 minutes). Add one-third cup of sugar and continue beating on med-high speed until stiff peaks form (another 1 to 2 minutes). Set aside.
  4 egg whites, 1 cup granulated sugar
• In a medium bowl, whisk together the egg yolks, oil, milk, vanilla extract, two-thirds cup of sugar, and lemon zest.
  1 cup granulated sugar, 5 egg yolks, 2 tablespoons vegetable oil, 3 tablespoons whole milk, 1 teaspoon vanilla extract, 1 tablespoon lemon zest
• In a small bowl, whisk together the flour, cornstarch, baking powder and salt.
  ¾ cup all purpose flour, 2 tablespoons cornstarch, 1 teaspoon baking powder, ¼ teaspoon fine sea salt
• Stir dry ingredients into the wet just until combined.
• Fold egg whites into the batter until fully incorporated.
• Pour batter onto prepared baking sheet and bake for 15 minutes or until the top of the cake is light brown. Let cool completely.

Filling

• In a small bowl combine the strawberries, one tablespoon of sugar and lemon zest.
  1 pound strawberries, 1 tablespoon sugar, 1 tablespoon lemon zest
• In a large bowl, beat the heavy cream on high speed until soft peaks form.
  1 cup heavy whipping cream
• Add the sour cream, vanilla extract, and powdered sugar. Continue beating until stiff peaks form.
  1 tablespoon sour cream, ½ teaspoon vanilla extract, ¼ cup powdered sugar
• Spread onto the cooled cake leaving a one inch border around the edges.
• Scatter strawberries over the top of the whipped cream.
• Starting at the short end, roll up the cake, letting the parchment fall away as you roll.
• Place the cake seam side down.
• Dust with powdered sugar if desired.