Preheat oven to 180ºC . In frypan, brown meat, stirring till light brown & crumbly. Add onions, celery & green pepper. Cook for 3 min. Add tomatoes & simmer a few minutes. Add salt & pepper. Cook pasta; drain. In buttered 2 litre casserole, combine pasta, sauce & blue cheese. Sprinkle grated cheese on top. Bake in a 180ºC oven for 20 min.