Place an oven rack in the center of the oven and preheat to 200 degrees F. Line 2 baking sheets with parchment paper.
In a stand mixer fitted with a whisk attachment, beat the egg whites, cream of tartar and salt until the mixture holds soft peaks, about 1 minute. With the machine running on medium-high speed, add the sugar, 1 tablespoon at a time. Increase the speed to high and beat until the mixture is thick and holds stiff peaks, 3 to 5 minutes. Add the vanilla extract. Using a spatula, fold in the strawberries and lemon zest, taking care not to deflate the batter.
Using a 1/4-cup-size ice cream scoop, scoop heaped mounds of batter onto the prepared baking sheets, spacing each about 2 inches apart. Bake for 2 hours. Turn off the oven and allow the meringues to cool completely while still in the oven, about 2 hours.
The meringues can be stored in an airtight plastic container for up to 4 days.
Recipe courtesy of Giada De Laurentiis