Preheat oven to 220°F. Whip aquafaba with cream of tartar to soft peaks. Gradually add vanilla and sugar. Whip to stiff peaks.
Place a dollop of the meringue on all corners of a sheet pan to help secure a sheet of parchment paper on top. Scoop the meringue onto the sheet to form small mounds. Be sure to leave ample room around each mound. Use a spoon to form an indentation in the center for the filling later. Bake for about 2 hours. Turn off the oven and allow to cool completely inside of the oven with the door slightly open.
Meanwhile, make the cream by whipping aquafaba again with cream of tartar to soft peaks. Gradually add lemon juice and sugar and whip to stiff peaks.
When the pavlovas are cooled, fill each mound with the cream and then top with berries and powdered sugar.