Preheat oven to 200°F. Line a baking sheet pan with parchment paper. Flip a 9-inch plate onto the parchment paper and use the tip of a knife to outline, being careful not to cut all the way through the paper.
Pavlova: Pour the egg whites, salt and cream of tarter into the bowl of an electric mixer fitted with the whisk attachment. Whip together on medium-high speed until glossy peaks form. (Shiny peaks).
Whisk together 1 cup sugar and cornstarch in a separate bowl. Lower speed of mixer and gradually add sugar, about 3 Tbsp at a time. Beating just until stiff peaks form, don't overbeat. Add almond extract, mix on low just until combined.
Mound the beaten egg whites (meringue) onto the middle of the circle of the parchment paper lined pan, spreading into roughly a 9-inch circle. Leave the sides higher than center to form space to encase the filling.
Bake for 2 hours. Turn off oven leaving the meringue in the oven for another 2-3 hours or overnight.
Whipped Cream: Using an electric mixer, beat together cream, sugar and vanilla until stiff peaks form, don't overbeat. Spread into the middle of the pavlova.
Berries: Toss sliced strawberries with 1 Tbsp sugar, stir and let sit for a few minutes to macerate.
Spoon the fresh strawberries, fresh blueberries and fresh raspberries over the sweetened whipped cream leaving a border of cream and meringue.
Slice and serve immediately or chill until serving.