Preheat oven to 425F and spray a 9x13 inch baking dish with cooking spray.
Bring a large pot of salted water to a boil and add frozen vegetables.
Boil for 2-3 minutes until warmed through, then drain.
In a large bowl, mix cheddar soup, milk, garlic powder, onion powder, and black pepper until smooth.
Stir in 1 cup shredded cheddar cheese.
Add drained vegetables to cheese mixture and fold until coated.
Pour into prepared baking dish and top with remaining 1/2 cup shredded cheddar.
Bake for 20-25 minutes until bubbly and cheese is lightly browned.
Remove from oven and sprinkle crispy fried onions on top.
Bake for 5 more minutes until onions are golden and crunchy.
Let cool for 5 minutes before serving.