In large saucepan melt 2 tbsp butter. stir in flour until smooth, gradually add cream. bring to a boil; cook and stir for 2 minutes or until thickened.
Add 1 cup cheese, salt, mustard, dill, sage and cayenne. Stir until cheese is melted. Remove from heat and stir in shrimp.
pat salmon dry with paper towels. place in a greased 13x9 baking dish. Pour shrimp mixture over salmon and top with remaining cheese.
bake uncovered at 400 degrees for 25-30 minutes or until fish flakes easily and shrimp turns pink.
meanwhile, in a saucepan, saute garlic in remaining butter until tender. Add rice, cook and stir for 2 minutes. Stir in broth and bring to boil. Reduce heat and cook, covered, for 15 minutes or until rice is tender.