Begin by dicing the medium onion and finely chopping the carrots until they are small enough to blend seamlessly into the soup. Set the chopped veggies aside.

In your slow cooker, layer in the frozen broccoli florets, chicken broth, diced onion, and carrots. Add the cream of celery soup along with the seasoned salt, black pepper, and cayenne pepper. Stir gently to combine.

Cover the slow cooker and set it to high for about 4 hours. The carrots should be tender and the vegetables fragrant when ready.

For a creamier texture, blend the soup directly in the slow cooker with an immersion blender or in batches in a regular blender.

Stir in the Velveeta and grated sharp cheddar cheese, mixing thoroughly and let it sit on low for 10-15 minutes to melt the cheese.

Taste the soup and adjust the seasoning if needed before serving with crusty bread or crackers.