set oven to 375 degrees f. in a lrg stewer, add the potatos and cover with cold water and add salt. Bring to a boil over med-high heat and cook the potatoes till soft and tender, about 20 to 25 min. Drain well and mash them with the milk, butter, 1/2 teaspoon salt, and 1/2 teaspoon pepper.
meanwhile, heat the oil in a lrg skillet over med-high heat. cook the onions and carrots until soft, 10 min. Add the ground beef and cook, breaking up the meat, well browned. season with the rosemary, 1/2 teaspoon salt, and one teaspoon pepper. stir in the tomato paste and chicken broth and let simmer 5 min. stir in the peas.
Scrape the ground beef mixture into a ungreased 1 1/2- quart baking dish. top with the potato mixture. Bake 30 minutes or until golden. cool slightly and serve.