1. Place tempeh slices in large baking dish. Bring wine, herbes de Provence, oil, garlic, and pepper to a boil in small saucepan. Pour over tempeh, cover, and refrigerate 4 hours, or overnight.
2. Preheat oven to 400°F. Coat baking sheet with cooking spray. Remove tempeh from marinade, and place on baking sheet, reserving marinade. Spray top of cutlets with cooking spray, and bake 15 minutes. Flip tempeh, spray again with cooking spray, and bake 15 minutes more, or until edges are golden.
3. Meanwhile, strain reserved marinade into small saucepan. Bring to a boil, and add bell pepper. Simmer 5 to 7 minutes, or until bell pepper is softened and liquid is nearly absorbed. Add tomato sauce, capers, and sugar, and season with salt and pepper, if desired. Simmer 10 minutes over low heat, or until sauce is thick. Stir in basil.
4. Place tempeh on plates, and divide sauce between servings. Garnish with basil sprigs, if desired.