In a medium bowl, toss strawberries and raspberries with sugar and lemon zest to evenly coat. Set aside.
Place meringue cookies in a zip-top bag and, using a rolling pin or a wine bottle, crush until coarsely ground. Set aside.
In the bowl of a stand mixer or hand mixer fitted with a whisk attachment, whisk heavy cream, powdered sugar, vanilla extract, and salt on medium speed until medium soft peaks form, about 4 minutes.
To Assemble: Cover bottom of each of four 12-ounce glasses with 2 tablespoons of the prepared berries. Top with a layer of whipped cream, followed by crushed meringue cookies. Repeat until glasses are full. (Alternatively, you can assemble Eton Mess in a large serving dish, such as a trifle bowl.)
