Heat the oven to 190c or 374f, prepare a baking or casserole dish. Heat the oil and once warm fry the leeks until soft then put them in baking/casserole dish. In the same pan and oil, or add more oil if needed, cook onion until soft and translucent. Next add meat and cook until cooked through, drain all the liquid and fat, then add garlic and cook for 2 minutes. Next add peppers, puree, salt, pepper, and broth and mix until well combined. Over medium low heat, bring to gentle boil then add flour to thicken up a bit. Taste and adjust salt and/or pepper if desired. Lastly, pour the pan ingredients over the leeks in casserole dish, place in the centre of the oven (uncovered) and bake for 1 hour. Nearly all of the liquid will have evaporated and the peppers will be very soft. Serve over mashed potatoes. (You might want to start the mashed potatoes one half hour into the cooking time of the casserole.)
Notes
MAKE IT VEGETARIAN: To make this dish vegetarian omit the minced beef and substitute it with mushrooms or eggplant or a variety of your favourite vegetables.
MAKE IT PRETTY: The dish is not an attractive one right out of the oven. Make it look pretty by serving it over the mashed potatoes and by using chopsticks to pull up some bits of leeks and peppers. Just use my photos as inspiration.:)
Recipe by Spicie Foodie ™ at https://www.spiciefoodie.com/2014/02/05/earth-eats-albanian-baked-leeks-or-tave-me-presh/