Bring a large pot of salted water to a rolling boil. Add the frozen vegetables and boil for 2 to 3 minutes, just until warmed through.

Drain the vegetables well and set aside.

In a large bowl, whisk together the cheddar cheese soup, milk, garlic powder, onion powder, and black pepper until smooth.

Stir in 1 1/2 cups of the shredded cheddar cheese until just combined.

Gently fold the drained vegetables into the cheese mixture until evenly coated.

Transfer the mixture to the prepared baking dish and sprinkle the remaining 1/2 cup shredded cheddar cheese on top.

Bake for 20 to 25 minutes, until bubbly and heated through.

Remove from the oven and evenly sprinkle the crispy fried onions over the top.

Return to the oven and bake for an additional 5 minutes, or broil for 1 to 2 minutes until the onions are golden and crisp.

Let the casserole rest for 5 minutes before serving.