Preheat oven to 275 degrees. Line two large backing sheets with parchment paper and set aside. In a large bowl, beat the egg whites, cream of tartar and salt for about 2-3 minutes, starting on low speed and working your way up to medium speed. Beat until there are small bubbles. In a second bowl, mix the sugar and cocoa powder. Add the vanilla extract. Continue whisking on high speed until the batter is glossy and stiff peaks form. Spoon the batter out onto your prepared baking sheets. Create several small pavlovas or two large pavlovas. Be careful not to make them too thin as they will spread out during baking. Decrease oven temperature to 250 degrees and cook for 50-60 minutes, until the pavlovas are crisp. Make the whipped cream by whipping the cream until it thickens and add powdered sugar. Assemble by layering pavlova, whipped cream, fresh berries and drizzle with Blackberry Patch Syrup. We used 3 flavors (Blueberry, Blackberry, and Strawberry). Serve immediately after assembling.