Heat oven to 425F.
In boiling water, blanch broccoli until still crisp and color
brightens; drain and place in baking dish.
Place fish in single layer over top.
In small saucepan, melt butter; add flour and cook, stirring,
for 1 minute. Add milk and cook, stirring constantly, until
thickened; approximately 3 minutes. Stir in cheese, dill, and
salt and pepper to taste until cheese has melted; pour over
fish. Bake, uncovered, for 15 - 20 minutes, or until fish flakes
easily when tested with fork.