Preheat oven to 250 degrees. Line a baking sheet with parchment paper, cutting a 10-inch circle from the paper.

In a large bowl, combine egg whites and cream of tartar. Beat at medium-high speed until foamy. Gradually beat in the sugar, a tablespoon at a time. Continue beating until stiff peaks form. Fold in the vinegar and almond extract.

In a small bowl, combine the cocoa and cornstarch. Mix well and gently fold into the egg white mixture. Spoon this mixture onto the circle of parchment paper. Bake for 1 1/2 hours. Turn oven off and let meringue cool completely in the oven.

Beat the cream and powdered sugar until stiff peaks form. Add in the sour cream, Nutella and vanilla. Mix cover, and chill.

Pit and cut cherries in half and set aside.

Just before serving, assemble the pavlova by spooning the cream over the center of the meringue, and then place the cherries on top of the cream. Garnish with fresh mint and serve.