Preheat oven to 350 degrees. Line a jelly roll (10x15”) pan with foil and spray with cooking spray. (Use the spray with flour or actually grease and flour the foil to avoid sticking.)
Beat eggs at high speed for 2 minutes, until frothy and dark yellow. Beat in sugar, lemon juice, and zest.
Whisk together salt, baking powder, and flour. Stir into wet ingredients just until blended.
Spread in prepared pan. Batter will be in a very thin layer and you will need to use a wooden spoon or spatula to spread it to all the corners of the pan. Bake for 9-11 minutes (mine took 10).
While the cake is baking, set a clean kitchen towel out on a large work surface. Sprinkle liberally with powdered sugar (about 1/4 cup). As soon as the cake comes out of the oven, turn it over on the kitchen towel sprinkled with powdered sugar. Remove foil carefully.
Working at the short end, fold the edge of the towel over the cake. Roll tightly, rolling up the cake into the towel. Let cool completely while rolled, at least one hour.
While the cake is chilling, make the filling. Beat the heavy whipping cream and powdered sugar until stiff peaks form.
Gently fold in the lemon curd. Chill until ready to use.
When cake is cool, carefully unroll the towel. Spread the lemon whipped cream over the cake. (You might have some whipped cream left over.) Gently but tightly, re-roll the cake and wrap it in plastic wrap. Chill until it firms up a bit, at least one hour or overnight. Slice and serve. Cake will last covered in the refrigerator for up to 4 days.