• Place the uncooked ground meat in an even layer in the bottom of a 4-quart slow cooker.
• Top with the minced garlic and mushrooms.
  
• In a medium bowl, whisk together the beef broth, tomato paste, Worcestershire sauce, oregano, garlic powder, and onion powder.
• Pour the broth mixture over the contents of the slow cooker and stir to combine.
  
• Cover the slow cooker and cook on low for 4-6 hours or on high for 2-4 hours, until the beef is cooked through.
  

For the Mashed Potato topping

• Make the mashed potatoes about 15 minutes before the slow cooker time ends. Peel and cut the potatoes into 2-inch cubes.
• Place the potatoes in a medium saucepan and cover them with 2 inches of water and a sprinkle of salt. Bring the potatoes to a boil over medium-high heat for about 15 minutes until fork tender.
• Drain the potatoes and place them in a bowl.
  
• Add the milk, butter, salt and pepper to taste.
  
• Gently mash the potatoes with a handheld potato masher or mixer until just combined.
• Mix the cheddar into the mashed potatoes and set aside.

To Finish

• Mix the flour and water until smooth in a small bowl, then slowly stir the mixture into the slow cooker.
  
• Add the peas and carrots.
  
• Spread the mashed potatoes in an even layer on top of the meat mixture.
  
• Cover the slow cooker and cook on high for 30 more minutes, until the gravy has thickened and the mashed potatoes are heated through.