Steam or boil broccoli florets until just cooked, about 2-3 minutes - drain water well.
In a large saucepan melt 2 tablespoons butter over medium-low heat. Stir in flour. Add cream cheese, blue cheese, salt, and milk. Stir over heat until smooth. Stir in broccoli being careful to not break apart broccoli and pour into an 8x8 or 9x9 oven-safe dish.
Mix 6 tablespoons melted butter with cracker crumbs until well combined. Stir in 1 cup of cracker mixture into broccoli mixture. Pour mixture into a casserole dish.
Bake covered for 15 minutes.
Remove from oven and sprinkle the top with remaining cracker crumbs. Return to oven and bake uncovered for another 15 minutes.
Allow to cool for 10 minutes before serving.
This can be prepared the day before and you will need to add 25 minutes to your cooking time if it has been refrigerated.