Melt 1 tbsp. of butter in a medium skillet over medium heat. Add the onion and sauté until translucent, about 5 minutes.
Add the garlic and cook just until fragrant, about 1 minute.
Add the mushrooms and mix well. Sauté until the mushrooms are soft, about 3-5 minutes.
Remove the onions, mushrooms and garlic to a plate.
Add the ground beef to the skillet and cook until browned, breaking it up with a wooden spoon as you go.
Drain excess fat from the ground beef. Add 1 tbsp. of Worcestershire sauce and 1 tbsp. of butter to the skillet with the beef. Stir until the butter is melted.
Add the salt, pepper, smoked paprika, and beef broth. Add the onions, mushrooms, and garlic back into the skillet. Stir gently to combine.
Reduce the heat to low and simmer for 20-30 minutes, or until the much of the broth has evaporated and a thicker sauce remains. Stir often to prevent burning.
Serve on toasted Kaiser rolls with toppings of your choice. We like to spread ours with some garlic butter. You can serve with or without cheese; sliced provolone is a great addition.