In a large skillet, brown the turkey and season with salt.
When the turkey is browned, add onion, garlic, black beans, cilantro, serrano pepper, diced tomatoes, and cumin. Mix well and simmer on low, covered for 5 minutes.
Remove lid, add corn and simmer an additional 5 minutes or until all the liquid reduces.
Preheat oven to 350.
Cut peppers in half lengthwise, removing seeds and stem.
Place peppers, cut side up in an oven-proof dish. Fill each pepper with 0.5 cup turkey mixture. Pour about 0.33 cup water or chicken broth on the bottom of the dish.
Cover tightly with foil. Bake 50 minutes, or until the peppers are tender.
Remove foil, top each with 1.5 tbsp of cheese and bake uncovered an additional 5 minutes.
Top with chopped scallions and serve with a dollop of reduced-fat sour cream if desired (optional).
Notes
Best served with a light salad for a balanced meal.