1. Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper or lightly grease a loaf pan.
2. In a skillet over medium heat, add olive oil and sauté onions and bell peppers until they are soft and translucent, about 5 minutes. Add garlic and mushrooms (if using) and cook for an additional 2 minutes. Remove from heat and let cool slightly.
3. In a large mixing bowl, combine the ground beef, breadcrumbs, milk, egg, Worcestershire sauce, ketchup, salt, and pepper. Add the sautéed vegetables and mix until just combined. Be careful not to overwork the meat mixture to keep the meatloaf tender.
4. Place half of the meat mixture into the prepared loaf pan or shape into a loaf on the baking sheet. Create a small well in the center and fill with shredded cheese, then top with the remaining meat mixture, sealing the edges to encase the cheese.
5. Spread a thin layer of ketchup over the top of the meatloaf for extra flavor and moisture.
6. Bake in the preheated oven for 45-55 minutes, or until the internal temperature reaches 160°F (70°C). Let the meatloaf rest for 10 minutes before slicing—this helps retain its juices and makes for cleaner slices.

As my grandma used to say, “Take your time, and let the flavors speak for themselves.” Following her advice, this meatloaf is all about patience and love.