In a stock pot, saute onion and celery in butter just until tender. Add in the potatoes, carrots, water, bouillon, salt, basil, and pepper.
Bring to a boil. Reduce to a simmer, cover and cook for 20 minutes or until potatoes are tender. Add in the zucchini and frozen corn.
Add in 2/3 cup of the evaporated milk. With the remaining 1/3 cup evaporated milk, mix in 1 tbsp flour and into pot. Stir in and cook until it begins to thicken. Remove from heat and mix in cheese until melted. Serves 4-6.