Broccoli Cheddar Soup

COMFORT FOOD!  Started loving this soup at Panera Bread back in the day!  Couldn't get enough of it!  Finally figured I'd probably save myself SO MUCH MONEY if I stopped buying it at Panera and made it for myself at home! :)  Have made it ever since! 

1/2 onion, chopped
1/4 c butter
broccoli (they usually have three in one rubberband), chopped
2 (14 oz) cans chicken broth
1 lb cheddar cheese, shredded
1 c milk
1 1/2 t garlic powder
1/3 c cornstarch
1/2 c water

Melt butter.  Cook onion in butter til soft. Stir in broccoli and cover with chicken broth.  Simmer until broccoli is tender, 10-15 minutes.  Reduce heat, stir in cheese until melted.  Mix in milk & garlic powder.  In small bowl, stir cornstarch into water until dissolved.  Mix into soup.  Cook & stir until thick.  Serve.