Step 1: In a large Dutch oven or heavy-bottomed pot, cook the diced bacon over medium heat until crispy. Remove the bacon with a slotted spoon and set aside, reserving 1-2 tablespoons of bacon fat in the pot.
Step 2: Add the chopped onion and celery to the reserved bacon fat. Cook until softened and translucent, about 5-7 minutes. Add the minced garlic and cook for another minute until fragrant, being careful not to burn it.
Step 3: Sprinkle the flour over the softened vegetables and cook, stirring constantly, for 1-2 minutes to create a roux.
Step 4: Slowly whisk in the chicken or vegetable broth until smooth. Add the diced potatoes and any scraped corn cobs (if using fresh corn). Bring to a simmer.
Step 5: Reduce the heat to low, cover, and simmer for 15-20 minutes, or until the potatoes are fork-tender. Remove and discard any corn cobs.
Step 6: Stir in the corn kernels, whole milk, and heavy cream. Season with salt, black pepper, and a pinch of cayenne pepper (if using). Heat through until the chowder is hot and slightly thickened, about 5-10 minutes. Do not boil once the cream is added.
Step 7: For an extra smooth chowder, carefully blend 1-2 cups of the chowder using an immersion blender or transfer a portion to a regular blender (blend in batches) and then return it to the pot.
Step 8: Ladle the hot corn chowder into bowls. Garnish with the reserved crispy bacon and fresh chopped chives or parsley. Serve immediately.