Meringue "Cupcakes" with Berry Sauce

Directions

1. 1. Preheat oven to 225 degrees F. Line every other cup of a nonstick 12-cup muffin tin with baking cups; coat with cooking spray. Whisk egg whites, vinegar, vanilla, and salt with a mixer on medium-high speed until frothy. Add the sugar, 1 tablespoon at a time, beating for 1 minute after each addition, making sure the sugar dissolves. Beat until stiff, glossy peaks form. Mix in 6 drops food coloring.
2. 2. Transfer mixture to a pastry bag fitted with a plain coupler (no tip), and pipe into prepared baking cups, about 2 inches above rims, finishing with a peak in the centers. Bake, rotating halfway through, 3 to 3 hours and 20 minutes. (Cupcakes should be completely dry on the outside but still soft in the middle. A toothpick inserted horizontally at base of top should have moist but cooked crumbs attached.) Transfer cupcakes in baking cups to wire racks; let cool completely.
3. 3. You can place the “cupcakes” into small bowls or on small plates and use a spoon to break them or carefully slice off tops of cupcakes using a serrated knife. (Run the knife just above the liner and slowly work your way to the center.) Top each cupcake with 2 tablespoons blackberry sauce, a few blackberries, and 2 tablespoons low-fat yogurt. Replace tops, and serve immediately.
4. 4. Whisk all blackberry sauce ingredients in a heatproof bowl set over a pan of simmering water until slightly thick, 8 to 10 minutes. Strain; refrigerate until cold and thick.