Preheat the oven to 350°F. Line a baking sheet with parchment paper and grease lightly.
Heat the olive oil in a medium saute pan over medium heat. Add in the onion and bell pepper. Cook, stirring often, until softened, about 5-7 minutes. Remove from the heat and let cool.
1 tablespoon olive oil, 1 medium yellow onion, 1 green bell pepper
In a large bowl, mix together the Ritz crackers, eggs, cheese, milk, salt and pepper until combined.
45 Ritz crackers, 2 large eggs, 1 cup freshly shredded cheddar cheese, ½ cup whole milk, 1 teaspoon kosher salt, ¼ teaspoon ground black pepper
Add in the ground beef and cooled pepper/onion mixture and mix with your hands until the ingredients are evenly distributed.
2 pounds 80% lean ground beef
Turn the mixture out onto your prepared pan. Shape it into a loaf and bake for 30 minutes.
In a small bowl, stir together the ketchup, brown sugar, and mustard.
⅔ cup ketchup, 2 tablespoons brown sugar, 1 teaspoon yellow mustard
After the meatloaf has cooked for 30 minutes, spoon the glaze over the meatloaf and spread it out to evenly coat. Bake for another 30 minutes or until cooked through.
Cool for 10-15 minutes before slicing and serving.