Add the olive oil to the bottom of your slow cooker and spread it around lightly with a spoon or brush so the vegetables do not stick.

Place the potato chunks in an even layer in the bottom of the slow cooker, followed by the carrot slices and sliced onion.

Sprinkle the minced garlic evenly over the potatoes, carrots, and onions.

In a medium bowl, whisk together the beef broth, 1 cup of water, tomato paste, Worcestershire sauce, dried thyme, dried rosemary, kosher salt, and black pepper until the tomato paste is fully dissolved.

Pour the broth mixture evenly over the vegetables in the slow cooker.

Add the frozen fully cooked beef meatballs on top of the vegetables, spreading them out into an even layer so they cook evenly.

Cover the slow cooker with the lid and cook on LOW for 4 to 5 hours, or until the potatoes and carrots are tender and the meatballs are heated through.

About 20 minutes before serving, whisk the cornstarch and 2 tablespoons of cold water together in a small bowl to make a smooth slurry.

Gently stir the cornstarch slurry into the liquid in the slow cooker, being careful not to break up the potatoes too much.

Cover and cook on HIGH for 15 to 20 minutes, or until the sauce has thickened into a light gravy.

Taste the gravy and add a little more kosher salt or black pepper if needed.

Serve the Frozen Meatball Pot Roast hot, spooning the meatballs, vegetables, and gravy into bowls or onto plates, and sprinkle with chopped fresh parsley if using.