Cook the vegetables. Heat olive oil in a skillet. Add onions and bell pepper, and stir, cooking for 6 minutes or until soft and tender. Set aside to cool.
Mix the meatloaf ingredients. In a large bowl, combine the ground crackers, paprika, eggs, cheddar, and milk. Stir to combine. Add ground beef and season it all with salt and pepper.
Combine. Add the cooked onions and peppers to the beef mixture. Stir with a spatula or knead it with clean hands. Let the mixture rest for 10 minutes.
Bake the meatloaf. Transfer the beef mixture to a loaf pan and bake it for 30 minutes.
Meanwhile, make the glaze. In a saucepan, add all the topping ingredients: ketchup, dark brown sugar, and mustard. Simmer over medium heat until the sugar is dissolved, about 3 to 4 minutes.
Coat the meatloaf. Remove the meatloaf from the oven and brush on the topping/glaze with a BBQ brush or spread it with a spoon. Continue to bake the meatloaf for another 30-40 minutes or until the meatloaf's internal temperature registers at 160˚F.
Finish and serve. Pull the meatloaf out of the oven and let it rest for 15 minutes before slicing and serving it with mashed potatoes and peas.
Notes
Glaze alternatives: You can use BBQ sauce instead of making the topping.
Ground beef: Use 80% lean ground beef. Beef with fat content will shrink, and your meatloaf will contain too much liquid.
Don't overmix: Try not to overmix the meatloaf. Overmixing can make the meatloaf dense and dry instead of tender and juicy.
Internal temp: For juicy results, cook the meatloaf until its internal temperature reaches 160ºF to 165˚F, max.