Heat butter in a pan, then cook onion, garlic, celery, pepper and potato for 5 mins. Stir in milk and stock, bring to the boil, then simmer for 15 mins. Stir in corn, cook for 3 mins, then add Tabasco and seasoning.
For the croûtons, place the bread in a bowl with the garlic, oil and some salt, toss well. Heat a non-stick pan, then gently cook cubes until golden and crisp. Serve the soup topped with the chives and croûtons.