In a large bowl, combine the ground beef, breadcrumbs, egg, shallot, Worcestershire sauce, cloves of garlic, ketchup, mustard powder, and salt and pepper.
Once everything is mixed, shape them into 4-5 patties.
In a skillet, add one teaspoon of olive oil over medium-high heat. Cook the patties in batches or a single layer; cook for 1-2 minutes or until both sides are brown.
Remove the meat from the pan and pour off any excess fat.
Add the second teaspoon of olive oil and toss in the mushrooms; cook over medium-high heat for 3-5 minutes or until the mushrooms are softened.
Stir in the flour and gradually add the beef broth, stirring occasionally.
Once the mixture becomes smooth, add your beef back to the pan and reduce the heat to low-medium.
Spoon the gravy over your patties, cover the pan and let simmer for 7-10 minutes or until patties are thoroughly cooked.