Sauté onions, carrot, red bell pepper and celery in 2 tablespoons of butter until softened.
Add lemon juice, water and cauliflower to the pan.
Stir to mix all vegetables together and cover the pan.
Steam on low for about 10 minutes or until cauliflower is tender.
Stir in cream cheese, 1/2 cup Parmesan cheese and salt to taste into the cauliflower.
In a bowl, mix panko crumbs, 1/4 cup Parmesan cheese, 1 teaspoon salt and 1 tablespoon melted butter and sprinkle on top of cauliflower.
Broil for 1 minute or so (watch it closely) until the topping is browned