Prepare the Meat Mixture

1. In a large mixing bowl, combine ground beef, eggs, breadcrumbs, milk, finely chopped onion, bell pepper, garlic, Worcestershire sauce, ketchup, salt, pepper, thyme, and smoked paprika.
2. Mix gently until just combined. Do not overmix.

Shape the Meatloaf

1. Form the mixture into a loaf shape that will fit inside your slow cooker.
2. Place a sheet of parchment paper or aluminum foil at the bottom of the crockpot for easier removal, if desired.

Prepare the Vegetables

1. In a large bowl, combine cubed potatoes, carrots, and onion chunks.
2. Drizzle with olive oil and toss to coat.
3. Sprinkle with dry onion soup mix and stir until vegetables are evenly seasoned.

Assemble in Crockpot

1. Place the shaped meatloaf in the center of the slow cooker.
2. Arrange the seasoned vegetables evenly around the meatloaf.
3. Cover with the lid and cook on Low for about 6 hours, or until the internal temperature of the meatloaf reaches 160°F and the vegetables are tender.

Add the Topping

1. In a small bowl, whisk together ketchup, brown sugar, and mustard.
2. About 30 minutes before serving, spread the topping evenly over the meatloaf.
3. Cover and continue cooking until the topping is set and glossy.

Serve

1. Carefully lift the meatloaf out of the crockpot using parchment paper or large spatulas.
2. Let rest for 10 minutes before slicing.
3. Serve with the cooked vegetables on the side.