Tamale Pie

1. In a large skillet, saute the ground beef with the onion over medium-high heat, breaking up any large lumps of meat, until lightly browned, 7 to 8 minutes. Drain off any excess fat. 2. Stir in the bell pepper, chili powder, cumin, salt, and black pepper. Cook for another 2 minutes to toast the spices. Stir in the tomatoes, olives, and corn. Mix well. 3. Cut the polenta roll crosswise into 10 to 12 rounds about 3/4-inch thick. Use half of the slices to line the bottom of a 4-quart electric slow cooker, trimming the rounds as necessary to fit. Spoon the meat mixture over the polenta, spreading it evenly. Top with the remaining polenta slices. 4. Cover and cook on the low-heat setting for 4 to 4-1/2 hours. Remove the lid and sprinkle the cheese over the top of the tamale pie. Raise the heat setting to high and cook with the cover ajar for 10 minutes, or until the cheese is melted. Serve the tamale pie hot, garnished with sour cream and chopped cilantro.