Brown meat with onions in a skillet over medium-high heat. Stir in chili powder, cumin and salt. Add tomatoes and set aside.
Preheat oven to 350°F. Lightly butter inside of 8-inch casserole dish.
Spread ⅓ of cream cheese on a tortilla and place cheese side up in prepared casserole. Then add layers of ⅓ of black beans and ⅓ the meat mixture.
Repeat with 2 more layers of cream cheese spread tortillas, black beans and meat mixture -reserving about ¼ cup of meat mixture.
Add final flour tortilla, top with reserved meat mixture and sprinkle with grated cheese. Bake for 20 – 25 minutes or until heat through.