Preheat oven to 350°F. Line a jelly roll pan or 10x15-inch rimmed baking sheet with parchment paper and spray with baking spray.
Add the egg whites to the clean bowl of a stand mixer fitted with a whisk attachment. Whip at medium speed for 45 seconds, or until a microfoam has formed.
4 large eggs
Add in the salt and continue whipping for 30 seconds.
¾ teaspoons kosher salt
With the mixer still going, stream in 2 tablespoons of sugar.
⅓ cup granulated sugar
After the sugar has been incorporated, let the meringue continue to whip for 8-10 minutes while you make the yolk mixture.
In a separate medium-sized bowl, whisk the egg yolks, remaining sugar, and strawberry Jell-O together until the mixture is fluffy.
2 tablespoons strawberry Jell-O
Whisk in the milk and vegetable oil until well combined, then add in the flour and mix just until incorporated and smooth.
2 tablespoons milk, 1½ tablespoons vegetable oil, ¾ cup cake flour
Once the meringue has formed stiff peaks, use a rubber spatula to gently fold in the yolk mixture until fully combined and smooth.
Pour the batter onto the jelly roll pan and smooth out to the edges.
Place the pan into the preheated oven to bake for exactly 10 minutes.
Once baked, remove from the oven and place the cake (on the parchment) onto a cooling rack to rest for exactly 10 minutes.
Once the cake has cooled slightly, dust it with an even layer of powdered sugar.
Powdered sugar
Place a large kitchen towel over the cake. Roll the cake up with both the towel and the parchment paper into a log. Let the cake finish cooling completely for about 1 hour.