Method:
In a large saucepan over medium high heat, melt butter and sauté onion about 5 minutes, until tender. Mix in flour, coating the onion. Add broth and bring to a boil, whisking constantly until smooth. Reduce heat, add potatoes and simmer 20 minutes until tender. Slightly mash potatoes in soup, then stir in corn and milk. Cook another 5 minutes, remove from heat and stir in cheddar cheese. Season with salt and pepper. Garnish, if desired.