Preheat oven to 350 degrees F. Place chicken thighs into a 9x13 inch baking dish. Place cumin, paprika, garlic salt, salt and pepper into a small bowl. Mix to combine then sprinkle over tops of chicken thighs. Pour buttermilk over top, cover baking dish loosely with tin foil and bake for 1 hour. Remove and let rest for 10 minutes before serving. Serve with your favorite roasted vegetables and salad if desired.