In a large soup pot, melt butter over medium heat. Add onion, garlic, celery and a pinch of salt and pepper, and cook until softened and fragrant, about 5 minutes. Add red pepper and cook for 2 minutes.
Add beans, corn, chicken, cumin, paprika, red chili flakes and a pinch of salt. Stir gently, to bloom spices. Slowly add the broth, and bring to gentle boil. Reduce heat and simmer for 15 minutes, stirring occasionally. Taste, and season with salt and pepper, if desired.
Remove 3 cups (750 mL) of soup to a blender pitcher, and blend until smooth. Pour blended soup back into the pot, stirring to combine. Keep heat on low to simmer.
Meanwhile, turn the oven on broil. Cut off top of buns, and remove bread from inside to create a bowl. Save the bread chunks to dip in the chili, or for bread crumbs for future recipes.
Sprinkle a bit of cheese in the bottom of each bread bowl and arrange bowls on a cookie sheet, broiling for 3-5 minutes, until edges are starting to brown.
Fill bowls with a generous helping of chili, top with remaining cheese, broil again if you want melted cheese, then add a generous sprinkle of scallions. Enjoy!