Add the egg whites to a large mixing bowl and use a hand mixer or stand mixer to beat starting on low and increasing to medium until you get soft peaks, about 4 minutes. Gradually add the sugar with the beater running.
Beat for an additional 4 minutes until the mixture is thick, white, and glossy.
Line a baking sheet with parchment paper. Butter the parchment paper. Spread the meringue, leaving ½ inch of room around the perimeter. Bake for 30-32 minutes. Remove and allow to cool slightly.
Run a knife around the edges of the baking sheet to loosen the edges of the meringue.
Cover the meringue with a second piece of parchment paper. Gently place a second baking sheet on top of the meringue, then use oven mitts to flip the meringue over in order to invert the meringue on top of the second baking sheet.
Make the Lemon Filling
Add the egg yolks to a medium bowl and whisk.
In a medium saucepan, add the cornstarch, granulated sugar, salt, water, lemon zest, and lemon juice and whisk to combine. Bring a to a low simmer at medium heat, stirring occasionally.
Once the mixture reaches a simmer, pour ½ to ⅓ of the mixture into the egg yolk mixture, whisking constantly. Return the egg yolk mixture to the pan, continuing to whisk. Whisk for 1-2 more minutes, then remove from the heat. Pour into a separate bowl and allow to cool (this helps to prevent the bottom of the lemon mixture from burning in the still hot saucepan. Place the mixture in the fridge to allow it to cool faster.
Assembling the Meringue Roulade
Once the lemon mixture has fully cooled, spread it on the meringue leaving room on the short ends to roll the meringue.
Use the parchment paper to help roll the meringue over the lemon filling, starting with the short end and continuing until it is seam side down. Cut into slices and serve with powdered sugar, whipped cream, or berries.
Notes
Don’t Overcook the Meringue: If baked at 300 for 30 minutes, the meringue will have a light, fluffy, marshmallowy consistency, but too much longer and it gets tougher and sticky.Butter the Parchment Paper: The meringue has quite a bit of sugar, which makes it easy for it to stick to the parchment paper. Before layering on the meringue, butter the parchment paper and the edges of the baking sheet to prevent it from sticking.Don’t Skimp on the Sugar: I’ve tried making this with quite a bit less sugar, but it doesn’t work. It becomes brittle and doesn’t have enough structure. It falls apart when you try to roll it. If you’re looking to reduce the total amount of sugar in the dessert, then fill the meringue roulade with unsweetened whipped cream and either add berries into the cream or top it with fresh berries or fruit.Lemon Filling: If the lemon filling is too thick, add 1 tablespoon of water at a time to thin it out until you get your desired consistency.Whipped Cream and Berries: For an even lighter and less sweet dessert, make fresh whipped cream and berries and line the meringue with the berries and cream, or just cream and then top it after its rolled with berries. To make the whipped cream, use 2 cups with cream with 1 tablespoon powdered sugar or maple syrup, or even plain without sugar and whip until you get stiff peaks (that way it holds up better when rolled).