Preheat oven to 350
Prepare rice and beef according to package instructions.
Combine sour cream, salsa and soup in a bowl.
Spread half the sour cream mixture on bottom of a 9x9 casserole dish and top with half of the torn tortillas. Add half of the rice. On top of the rice add half of the black beans. Over the beans place half of the beef and then half a cup of cheese. Repeat layer and end with remaining cup of cheese.
Bake at 350 for 25 minutes.
Top with guacamole if desired.