Toss together lightly but thoroughly the rice, butter, lemon juice and mustard.
Add onions, sour cream and olives; mix gently.
Lightly toss in blue cheese.
Turn into a 11/2 quart casserole; cover and bake in moderate oven (350Â°F.) about 30 minutes.
Makes 4 to 6 servings.
When you combine ingredients, it is im- portant to add the cold and firm blue cheese cubes last of all, just before baking, so that they will remain as distinctive little nuggets of melted cheese through the baking.
Just before serving, garnish the casserole top with a few whole olives.