Salisbury Steak with Garlic Mashed Potatoes and Mushroom & Onion Gravy

Ingredients:
For the Salisbury Steak:
1 1/2 pounds ground beef
1/3 cup breadcrumbs
1 egg, beaten
2 teaspoons Worcestershire sauce
1 teaspoon garlic powder
Salt and pepper to taste
2 tablespoons olive oil
For the Garlic Mashed Potatoes:
2 pounds potatoes, peeled and quartered
4 cloves garlic, minced
1/2 cup milk
2 tablespoons butter
Salt and pepper to taste
For the Mushroom & Onion Gravy:
1 tablespoon olive oil
1 onion, thinly sliced
8 ounces mushrooms, sliced
2 cups beef broth
1 tablespoon Worcestershire sauce
2 tablespoons flour
Salt and pepper to taste