| 5 Large Egg Whites |
| 2 1/3 Cups Sugar |
| 1 Tbsp. Cornstarch |
| 2 Tsp. Vanilla |
| 1 Tsp. White Wine Vinegar |
| 2 Pinches of Salt |
| 3 1/2 Cups Chopped Rhubarb |
| 2 Tbsp. Sauterne Cooking Wine |
| 1 1/2 Cups Heavy Cream |
| 3 Tbsp. Powdered Sugar |
Preheat oven to 350 ° F. Lightly oil an 8″ springform pan and line bottom with parchment paper.
Beat egg whites on medium high speed until soft peaks form. slowly add 1 2/3 cups sugar while beating continuously until stiff, glossy peaks form, about 7 minutes. Fold in cornstarch,vanilla, vinegar and 1 pinch salt.Spoon meringue into prepared pan, smooth top level and leave center depressed with most meringue on the sides of pan. Transfer to oven and immediately reduce heat to 325°. Bake without opening oven door, until cake has a pale honey color, 70 minutes. Turn off oven; let meringue stand inside, without opening oven door, at least 1 hour and up to overnight. Center will sink and leave high, crisp sides.
While meringue is baking, place rhubarb, remaining 2/3 cup sugar, wine, and pinch of salt in a medium saucepan over medium heat. Simmer gently,stirring occasionally, until sugar is dissolved and rhubarb is tender and partially broken down, about 7 minutes. Transfer rhubarb to a bowl with a slotted spoon and continue to cook liquid until reduced by half. Pour liquid over rhubarb; let cool completely. Can be stored in airtight, refrigerated container for up to 1 week.
Just before serving, carefully remove cake from pan and place on a serving platter. Beat cream and add powdered sugar until soft peaks form. Pile 2 1/2 cups whipped cream into center of meringue, then spoon 1 cup rhubarb mixture over. Serve with remaining rhubarb mixture and whipped cream on the side.