Copycat Zupas Wisconsin Cauliflower Soup

3 tbsp butter 1 medium onion chopped ¼ cup flour ½ tsp salt 1 cup half and half 1 cup milk 1 ½ cups water 1 14.5 oz chicken broth 2.5 lbs cauliflower 1 teaspoon dijon mustard 1 ½ cups sharp cheddar cheese shredded ½ cup pepper jack cheese shredded

melt butter and chopped onion together in a large sauce pan and saute for approximately 10 minutes over medium heat until onion is golden in color add flour and stir to make a roux. heat while stirring for a couple of minutes slowly add half and half along with the milk. gradually add and stir the entire time following the milk, gradually add the water and chicken broth and stir constantly add chopped cauliflower and heat until boiled reduce heat and simmer covered until cauliflower is tender. this will take approximately 15 minutes place contents of saucepan into blender and blend until smooth. remove the center part of blender cover to allow steam to escape return cauliflower mixture to saucepan; heat over medium heat until hot, stirring occasionally. remove saucepan from heat; stir in mustard and cheese until melted and smooth serve soup topped with a little cheese for garnish