Lightly grease the inside of a large slow cooker. For easier removal, place strips of parchment paper or aluminum foil underneath the meatloaf, leaving enough overhang to use as handles.

Add the ground beef, crushed buttery crackers, diced onion, diced green bell pepper, eggs, milk, salt, black pepper, garlic powder, onion powder, and shredded cheddar cheese to a large mixing bowl.

Gently mix the ingredients with clean hands or a large spoon just until evenly combined. Avoid overmixing, which can make the meatloaf dense.

Form the meat mixture into a loaf and carefully place it in the prepared slow cooker.

In a small bowl, whisk together the ketchup, brown sugar, and yellow mustard until smooth.

Spread half of the glaze evenly over the top of the meatloaf. Reserve the remaining glaze for later.

Cover and cook on LOW for 5 to 6 hours or HIGH for 3 to 4 hours, or until the center of the meatloaf reaches an internal temperature of 160°F.

Carefully remove or drain any excess grease from around the meatloaf, if needed.

Spread the reserved glaze evenly over the top of the cooked meatloaf.

Cover and cook for another 10 to 15 minutes, or until the glaze is warmed through.

Carefully lift the meatloaf from the slow cooker and transfer it to a serving platter or cutting board. Let it rest for 5 to 10 minutes before slicing.

Slice and serve warm with mashed potatoes, green beans, macaroni and cheese, or your favorite side dishes.