Bring a large pot of salted water to a boil. Add potatoes and cook until tender but still firm, about 15 minutes.
Drain and mash.
Mix in butter, finely chopped onion.
Season with salt and pepper to taste; rosemary & chives and set aside.
Preheat oven to 375 degrees F (190 degrees C.)
Add ground beef and onion and cook until well browned.
Pour off excess fat, then stir in flour and cook 1 minute.
Add ketchup, beef broth, and veggies.
Bring to a boil, reduce heat and simmer for 5 minutes.
Spread the ground beef mixture in an even layer on the bottom of a 2 quart casserole dish.
Top with the mashed potato mixture and sprinkle with remaining shredded cheese.
Bake in the preheated oven for 20 minutes, or until golden brown.