Combine the cauliflower, carrot, celery, water, and bouillon in a Dutch oven. Heat until boiling, then reduce to a simmer. Cover and cook for 12-15 minutes, or until the vegetables are tender. Do not drain the liquid.

In a separate large saucepan, melt the butter over medium heat. Mix in the flour, salt, and pepper, whisking until smooth. Gradually pour in the milk while stirring constantly. Bring the mixture to a boil and cook for 2 minutes, stirring, until it thickens.

Lower the heat and incorporate the cheddar cheese, stirring until fully melted. Add the hot pepper sauce, if using, for extra flavor.

Pour the cheese sauce into the Dutch oven with the cooked vegetable mixture. Stir thoroughly to combine and heat through before serving.