In a large pot, combine cauliflower, carrot, celery, onion, water and bouillon. Bring to a boil. Reduce heat, cover and let simmer for 15 minutes.
In a large saucepan, melt butter. Stir in flour, salt and pepper until smooth. Slowly add milk and bring to a boil over medium heat. Cook and keep stirring for a few minutes until thickened. Reduce heat and stir in cheese until melted. Add in the bacon if desired. Stir into the cauliflower mixture.Enjoy!