Heat the oven to 375 degrees. Coat 4 (8 to 10-ounce) ramekins with nonstick cooking spray. Place the ramekins on a small rimmed baking sheet.
Brown the ground beef in a large nonstick skillet over medium-high heat, stirring frequently.
When the meat begins to color, stir in the onion and mushrooms. Cook for 5 to 8 minutes over medium heat until the beef is browned and the onion and mushrooms are softened.
Stir in the flour, ½ teaspoon salt and pepper. Cook for 1 minute over low heat, stirring constantly. Slowly stir in the broth and Worcestershire sauce; bring to a boil and cook until thickened. Stir in the vegetables. Spoon the mixture into the ramekins.
Place the potatoes and garlic in a medium pot and cover with hot water. Bring to a boil over medium-high heat. Reduce the heat to medium-low and simmer for 10 to 15 minutes or until the potatoes are tender. Drain the potatoes and mash until smooth.
Stir in the sour cream and ¾ teaspoon. Spoon the mashed potatoes over the ground beef mixture.
Bake for 30 minutes or until the potatoes are lightly browned and the mixture is hot. Serve topped with the cheddar cheese, green onions and bacon.