Heat extra virgin olive oil and butter in a large skillet over medium-high heat then add the onions, season with salt, and saute until onions begin to turn golden brown, 3-4 minutes.
Add the peppers, season with salt and pepper, then continue sautéing until vegetables are crisp-tender, 3-4 minutes, turning heat down if vegetables begin to burn.
Add garlic then saute for 30 more seconds.
Transfer vegetables to a plate then let cool slightly.
Preheat oven to 425 degrees then line a baking sheet with foil and spray with nonstick spray.
In a large bowl combine ground beef, egg, Worcestershire sauce, Rice Chex or panko bread crumbs, cheese cubes, onions and peppers, and lots of salt and pepper then mix until combined.
Divide into 4 equal-sized portions then form into loaves and place on prepared baking sheet.
Bake for 20-22 minutes or until no longer pink in the center then serve.
Dividing a single meatloaf mixture into four individual portions limits baking time to twenty-two minutes at 425 degrees Fahrenheit. Achieving the right texture in these mini loaves requires careful management of moisture and binders.
Saute the chopped onions and green bell peppers in a 1:1 blend of extra virgin olive oil and butter for three to four minutes to drive off excess water before they enter the beef mixture.
Dice the provolone cheese into quarter-inch cubes rather than grating it so distinct pockets of melted dairy remain suspended throughout the ground beef during baking.
Incorporate half a cup of crushed rice cereal or panko bread crumbs to absorb released meat fats and prevent a dense, compact crumb structure.
Transfer the cooked vegetables to a plate and let them cool slightly before mixing into the raw beef to keep the fat from rendering prematurely.
Standard baking sheets lined with aluminum foil prevent sticking, though parchment paper serves as an effective substitute if foil is unavailable. Portion the meat into equal-sized loaves to ensure uniform internal cooking temperatures.