Cook broccoli until barely tender. Drain. Place in casserole.
Melt butter (can use same pan), add flour and chicken stock base.
Slowly add milk, stirring constantly, to make a smooth sauce.
Cook until it just starts to boil. Pour over broccoli.
Heat water in same pan, add the second butter.
When melted, turn off heat and add croutons and walnuts.
Top the broccoli with this mix, then sprinkle cheese over the top.
Bake at 400 degrees for about 20 minutes, or for 30 minutes if oven is at 350.
