Heat the oil in a pot over medium high heat
Add the ground beef and onion and cook until browned
Stir in the minced garlic and cook for 30 seconds
Add the beef broth, carrots, potatoes, mushrooms, bay leaf, garlic powder, and Worcestershire sauce
Bring to a boil
Reduce heat to simmer, cover, and cook for 10–15 minutes
Lower the heat to low
Mix the cornstarch with cold water in a small bowl to make a slurry
Add a spoonful of hot stew liquid to the slurry and stir to combine
Pour the slurry back into the pot
Whisk until smooth and stir until the stew thickens
If needed, turn up the heat slightly to finish thickening
If your stew gets too thick, it may have reduced itself while cooking, add a little water to thin it down
Remove the bay leaf
Taste and add salt and pepper as needed
Serve hot