In a skillet over medium heat, cook 3 lbs ground beef with ½ onion (chopped), 1 teaspoon minced garlic, and 1 teaspoon onion powder until the beef is browned. Drain excess grease.
Spray your crock pot with cooking spray.
Pour in the 10.5 oz cream of mushroom soup and stir to combine with the beef. Add the 16 oz bag frozen peas and carrots evenly over the beef mixture.
Cook on low for 6 hours.
In the last 2 hours of the cooking time, spread the mashed potatoes evenly over the top.