1. Preheat oven to 225 degrees. Line every other cup of 2 nonstick 12-cup muffin tins with baking cups; coat with cooking spray. Whisk egg whites, vinegar, vanilla, and salt with a mixer on medium-high speed until frothy. Add 1 3/4 cups 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. 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. Beat creme fraiche and remaining 1/4 cup sugar in a clean mixer bowl on medium-high speed until soft peaks form. 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 raspberry curd, a few raspberries, and 2 tablespoons creme fraiche mixture. Replace tops, and serve immediately.