Creamy Broccoli & Cheese Soup

INGREDIENTS

1/2 cup

salted butter

white onion, finely chopped

2 16 ounce packages

frozen chopped broccoli

4 14.5 ounce cans

chicken broth {reserve 1 cup for cornstarch mixture}

1 lb

loaf Velveeta cheese, cubed

1 cup

shredded cheddar cheese

2 cups

half-n-half

1 1/2 tsp

garlic powder

2/3 cup

cornstarch