How to Make It
Prepare the Meringues: Preheat oven to 400°F. Line 2 rimmed baking sheets with silicone baking sheets or parchment paper; set aside. (If you are using parchment paper, butter and flour the parchment. Before shaping the Meringues, dab a little bit of meringue at each corner of the paper to secure it to the baking sheet.)
Beat the egg whites, cream of tartar, and a pinch of the sea salt with a heavy-duty electric mixer fitted with the whisk attachment on high speed until frothy. Gradually add the granulated sugar, vanilla, and remaining sea salt, beating on high speed until stiff, glossy peaks form, about 3 minutes.
Using a rubber spatula or large ice-cream scoop, spoon 3 (3/4-cup) blobs of meringue onto each prepared baking sheet, leaving 2 to 3 inches of space between blobs. Using an offset spatula, smooth the top of each blob.
Reduce oven temperature to 175°F. Place the baking sheets in the oven; bake at 175°F until Meringues are crisp on the outside but interiors are still slightly wet, about 2 hours. (Check the consistency by poking into the bottom of 1 Meringue with your finger.) Turn on the oven light; turn off the oven, and leave the Meringues in the oven until fully dried, about 8 hours or overnight. (Poke again to make sure they are dry.)
Prepare the Blueberry Compote: Stir together sugar, water, and lemon zest in a 1-quart heavy saucepan, and bring to a boil over high. Boil, stirring occasionally, 5 minutes. Stir in the fresh blueberries; reduce heat to medium, and simmer, stirring occasionally, until the blueberries begin to burst, about 4 minutes. Remove from heat, and stir in finely chopped mint, lemon juice, and a pinch of sea salt.
When you are ready to serve, spoon about 1/4 cup warm or room temperature Blueberry Compote over each Meringue; garnish with mint leaves and a dollop of whipped cream.