Preheat the Oven by setting it to 350°F (175°C). Gather your ingredients and prepare your workspace.

Sauté the Vegetables by heating a splash of oil in a skillet and cooking chopped onions and green bell peppers for about 5-7 minutes until softened.

Combine the Ingredients in a large mixing bowl by mixing ground beef, crushed Ritz crackers, sautéed veggies, sharp cheddar, and milk until just combined.

Shape the Meatloaf by transferring the mixture into a greased loaf pan or shaping it on a baking sheet lined with parchment paper.

Prepare the Glaze by mixing ketchup and balsamic vinegar in a small bowl and pouring it over the meatloaf.

Bake the Meatloaf in the preheated oven for about 1 hour, until it reaches an internal temperature of 160°F (71°C).

Rest and Serve by allowing the meatloaf to rest for about 10 minutes before slicing and serving.