1 day before serving, line the bottom and sides of a 9"x5" loaf pan with parchment paper, letting it overhang the sides by 2"
In a medium bowl, beat heavy cream with a whisk or mixer until soft peaks form, about 2 minutes. Cover & refrigerate while you prepare the remaining ingredients.
Uncover the chilled lemon cream & whisk to loosen.
In a stand mixer, combine egg whites and salt & attach the whisk attachment.
In a small saucepan, stir together the ½ cup sugar, 2 tbsp of water, and corn syrup and cook over medium high heat. When syrup reaches 220℉, begin beating the egg whites in the mixer until soft peaks form. When syrup reaches 240℉, turn mixer to high and stream the hot syrup down the side of the bowl, without touching the whisk. Beat until meringue is stiff and shiny and the bowl is no longer warm, about 5 minutes.
Whisk ⅓ of the meringue into the lemon cream until just combined. Then fold in the remaining meringue in 2 additions with a rubber spatula, each time folding until just combined. Then add the chilled whipped cream and fold gently until just combined.
Cover and freeze overnight.