Cook the beef in a large skillet over medium high heat. Season with salt, pepper, and garlic powder and crumble as it cooks.
2 lbs lean ground beef, 1 tsp salt, 1 tsp pepper, 1 tsp garlic powder
Push the beef to edges of the pan, it will continue to brown, and add the butter to the clear part of the skillet. Once melted add the onions and peppers, stirring to coat. Continue cooking, stirring everything often, until they've softened and browned a bit- roughly 6 minutes.
4 tbsp butter, 1 medium yellow onion, 1 large green pepper
Reduce the heat to medium low and stir everything together then add the cream cheese and stir to combine. Continue cooking, stirring often, until melted, smooth, and evenly combined with the meat and vegetables. Remove the skillet from heat.
8 oz cream cheese
Add about 1/2 cup of beef mixture to each bun, top each with a slice of cheese, and serve immediately.
8 hamburger buns, 8 slices provolone cheese