5 large egg whites, room temperature

pinch of cream of tartar

pinch of salt

1 ¼ cups granulated sugar

5 tablespoons unsweetened cocoa powder

2 ounces bittersweet chocolate, finely chopped

1 ½ cup heavy cream, cold

½ cup sour cream (or Greek yogurt)

1 teaspoon vanilla extract

2 tablespoons sugar + 1 teaspoon

2 cups strawberries, cut in halves

1 cup raspberries

Preheat oven to 250 degrees F. Line a baking sheet with parchment paper.
In a large bowl, combine the egg whites with cream of tartar and salt. Beat the egg whites on medium-high speed until foamy, about 2 minutes. With mixer going, gradually beat in sugar, 2 tablespoon at a time. This will take about 3 minutes. Continue beating until stiff and shiny peaks form.
Sift the cocoa powder over the egg mixture and sprinkle in the chopped chocolate. Using a rubber spatula, fold to combine.
Spread the meringue onto the prepared baking sheet, making an 8-inch circle. Create a shallow well in the center.
Reduce oven temperature to 225 degrees F and bake until firm and dry, about 2 hours. Turn off oven and open the oven door. Let the meringue cool in oven completely, about 3 hours. Carefully remove the parchment and transfer to a plate.
For topping: beat the heavy cream, sour cream, vanilla extract and 2 tablespoons of sugar until soft peaks form, about 2 minutes. In a small bowl, toss the berries with remaining teaspoon of sugar.
Top the pavlova with whipped cream and berries. Serve immediately.