For the Pavlovas:

1. Preheat the oven to 250 degrees.
2. Using a 3-inch glass, bowl or round cutter, trace 6 circles onto two sheets of parchment paper (12 circles total). Transfer paper to two baking sheets, trace-side down.
3. In the bowl of an electric mixer (fitted with the whisk attachment), beat egg whites and salt on medium-high speed until soft, glossy peaks form.
4. Add sugar, 1 tablespoon at a time.
5. Beat on high until the meringue is stiff and glossy, about 5 minutes.
6. Add the cornstarch, vinegar, and vanilla. Fold gently until combined.
7. Using a spoon, scoop a mound of the meringue into the center of each circle. Use the back of the spoon to create a slight indentation in each of the mounds.
8. Transfer the baking sheets to the oven and bake until pavlovas are firm and dry to the touch but not browned, about 35-40 minutes.
9. Turn off the oven and let them cool (in the oven) for about an hour. Move to a wire rack and let them cool completely. 
10. When ready to serve, top with lemon curd, whipped cream, and fresh berries. Serve immediately.

For the Lemon Curd:

1. Mix together the lemon zest and sugar until zest is fully incorporated into the sugar.
2. Cream the butter in an electric mixer and then beat in the sugar mixture.
3. Add the eggs, one at a time. 
4. Then add the lemon juice and salt. Mix until combined. At this point, the mixture may look curdled. This is normal.
5. Pour the mixture into a 2-quart saucepan and cook over low heat, stirring constantly, until thickened (about 10 minutes). The lemon curd thickens at about 170 degrees F or just below a simmer.
6. Remove from heat and cool.
7. Can be stored in an air-tight container in the refrigerator for up to two weeks.

For the Whipped Cream:

1. Add cream, sugar, and vanilla extract to a mixing bowl (or the bowl of an electric mixer)
2. Using a whisk, a hand-held electric mixer, or a standing mixer, beat on low to medium until the mixture forms soft peaks.
3. Whipped cream can be stored in the refrigerator for several hours.