Bring the vinegar to a simmer in a medium saucepan over medium-low heat. Cook for 5 to 10 minutes, until the mixture has thickened and reduced to about 2 tablespoons. Stir in the strawberries, brown sugar, and salt and increase the heat to medium. Simmer for 5 to 6 minutes, mashing the strawberries with a potato masher, until the berries have softened and the sauce has thickened slightly. Remove from the heat and let cool slightly.
Whisk together the flour, cornmeal, brown sugar, baking powder, baking soda, and salt in a medium bowl. Whisk together the sour cream, melted butter, and egg yolks in a separate bowl. Make a well in the center of the dry ingredients and add the wet ingredients, whisking until well combined.
Place the egg whites in the bowl of an electric mixer fitted with the whisk attachment. Beat on medium-high speed for 3 to 4 minutes, until stiff peaks form. Gently fold the egg whites into the batter and mix just until no white streaks remain.
Preheat a waffle iron and spray generously with nonstick cooking spray. Cook the waffles according to the manufacturers’ instructions. Spoon the cooled strawberry sauce over the waffles and serve.