Preheat your oven to 350°F (175°C). Prepare your baking sheet with aluminum foil and cooking spray.

In a skillet over medium heat, add olive oil and sauté the onion and bell pepper for 5-6 minutes until softened.

In a large mixing bowl, combine ground beef, crushed Ritz crackers, milk, eggs, and cooled vegetables, then season and mix gently.

Shape the meat mixture into a loaf on the prepared baking sheet.

Bake the meatloaf in the preheated oven for 35 minutes.

Prepare the glaze by whisking together ketchup, brown sugar, Worcestershire sauce, and Dijon mustard.

Remove the meatloaf from the oven, pour the glaze over it, and bake for another 15-25 minutes until cooked through.

Let the meatloaf rest for 10-15 minutes before slicing.