01 -
In a medium bowl, whisk together chicken broth, steak sauce, and Dijon mustard. Set aside.
02 -
Heat a 30 cm skillet over medium-high heat. Add ground beef and cook for 7–8 minutes, stirring frequently, until fully browned. Drain excess fat and transfer beef to a plate.
03 -
Add butter to any remaining drippings in the skillet. Add sliced mushrooms, chopped onion, and steak seasoning. Sauté for 7–8 minutes until onions are translucent and mushrooms are golden.
04 -
Sprinkle flour over vegetables and cook, stirring constantly, for 1–2 minutes until the flour is browned and emits a nutty aroma.
05 -
Return the browned beef to the skillet. Pour in the prepared broth mixture and stir. Simmer for 3–4 minutes until mixture thickens to a rich consistency.
06 -
Spoon approximately 80 ml of meat mixture onto the base of each toasted burger bun. Top each with 1 tablespoon shredded Cheddar cheese, then cover with the top bun. Serve immediately.