In a skillet over medium heat, cook the ground beef with the onion (chopped), minced garlic, and onion powder until the beef is browned. Drain excess grease.
Spray your crock pot with cooking spray.
Pour in the the cream of mushroom soup and stir to combine with the beef. Add the 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.