Preheat oven to 400 degrees F. Split buns and lay them cut side up on a large baking tray (15×21). Lightly brush the cut sides with softened butter or mayonnaise (optional for crispier/more flavorful buns). Bake for 5 minutes to toast the buns. Meanwhile you can continue with the recipe:
Heat 1 tablespoon olive oil in a large cast iron skillet over medium-high heat. Add beef, onions and bell peppers and cook until beef is browned and onions are softened, about 7 minutes. Add garlic, and sauté 30 seconds.
In a liquid measuring cup (or small bowl), whisk the beef broth, cornstarch and beef bouillon together until smooth. Add to the meat mixture followed by the ketchup, Worcestershire sauce, Dijon and all seasonings.
Gently simmer over medium heat, stirring occasionally, until most of the liquid has been absorbed, but the mixture is still a little saucy, about 5 minutes.
Stir in the sharp cheddar cheese until melted. Taste and season with salt, pepper, red pepper flakes to taste (I like more salt). Keep in mind the flavors will be diluted with the cheese and buns.
Divide mixture between the bottom toasted buns and top each with a slice of provolone cheese. Bake (leaving both top and bottoms cut side up) at 400 degrees F for 5-10 minutes or until cheese is completely melted. Top the sandwiches and serve immediately.
NOTES
TIPS AND TRICKS
Beef bouillon: Is a secret ingredient that adds a complex depth of flavor. Use 1 ½ teaspoons of beef bouillon, better than bouillon, or granulated beef bouillon. If using cubes, use 1 1/2; crush and add directly to the sauce – don’t dissolve in water first.
Turkey: Feel free to replace the lean ground beef with lean ground turkey or ground chicken. To help it taste nice and beefy, omit the salt and add 2-3 teaspoons additional beef bouillon then add salt to taste. This is my secret in all my turkey recipes like my Turkey Chili and Turkey Tacos.
Recipe Variations: See post for many more tasty variations and fun ideas how to use the filling such as on potatoes, taquitos, grilled cheese, etc.
Prep Ahead: The filling can be prepped completely ahead of time and refrigerated then gently reheat on the stove. The filling can also be added to the slow cooker to stay warm for game time/party time/crowd time or simply ready for dinner/family time with just the lift of the lid. Now just toast those buns and you’re all set!
HOW TO STORE AND REHEAT
To store: Store the filling separately from the buns in an airtight container in the refrigerator for up to 5 days.
To freeze: The buns and filling freeze wonderfully if kept separate. To freeze the filling, let it cool completely then transfer to an airtight freezer safe container. Freeze for up to 3 months. When ready to eat, let meat thaw overnight before reheating.
To reheat in the microwave: Transfer small portions of the filling to a microwave safe dish, heat for one minute, stir then continue to heat at 30 second intervals.
To reheat on the stove: Rewarm the filling gently in a large skillet, stirring often. Add a splash of water if the filling seems dry.
Slow cooker: Heat on low for 1-2 hours.
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