Sling the butter into a soup kettle and melt over medium-high heat. Add the bacon and cook till crisp. Scoop out the bacon and drain on paper towels. Save for later--don't nibble too much.
Pour off all but 1/4 cup of fat from the pot. Toss in the onions and peppers, seasoning them with a pinch of salt and pepper. Cook till soft and then throw in the garlic, cooking it all for 1 minute more. Sprinkle on the flour and mix into the veggies. Dump in the broth and potatoes. Cover the pot and bring to a boil; then lower the heat and simmer for 10 to 12 minutes, or till the potatoes are tender. Add the shredded carrots and corn. Cover and simmer everything 5 to 6 minutes longer to blend the flavors.
Stir in the half-and-half. Season with the thyme, cayenne, some more salt, and lots of freshly ground black pepper to taste. Sprinkle with parsley and the bacon bits you've been saving. Give it one last stir, and ladle it up piping hot.