Creating the Slow Cooker Cowboy Casserole is straightforward if you follow these steps:

1. Brown the Meat: In a skillet over medium heat, brown the ground beef (or turkey) until fully cooked. Drain any excess fat.

2. Prepare Ingredients: While the meat is browning, chop the onion and bell pepper, and gather your other ingredients.

3. Combine in Slow Cooker: Transfer the browned meat to the slow cooker. Add the black beans, kidney beans, corn, diced tomatoes, taco seasoning, onion, bell pepper, and minced garlic. Stir well to combine all ingredients.

4. Season to Taste: Add salt and pepper according to your preference. Enjoy the aroma as you mix everything together!

5. Set the Slow Cooker: Cover and cook on low for 6-8 hours or high for 3-4 hours. Stir occasionally, if possible.

6. Add Cheese: During the last 30 minutes of cooking, sprinkle the shredded cheddar and Monterey Jack cheese on top. Allow to melt and blend into the casserole.

7. Finish Cooking: Once the cooking time is complete, check that everything is heated through and flavors are well blended.

8. Garnish: If desired, top with freshly chopped cilantro or green onions before serving.

These straightforward instructions will guide you in creating this hearty cowboy casserole effortlessly.