1. Preheat oven to 450°. Sauté tomatoes and 2 Tbsp. sugar in 2 Tbsp. melted butter in a large skillet over medium-high heat 10 to 12 minutes or until tomatoes begin to caramelize and turn light brown.
2. Stir together cornmeal mix, lemon zest, and remaining 6 Tbsp. sugar in a large bowl; make a well in center of mixture. Whisk together eggs, sour cream, and remaining 6 Tbsp. butter; add to cornmeal mixture, stirring just until dry ingredients are moistened. Fold in tomatoes.
3. Generously coat small (1/4 cup) brioche molds or muffin pans with vegetable cooking spray; spoon batter into molds, filling two-thirds full. Bake at 450° for 15 to 17 minutes or until wooden pick inserted in center comes out clean.