I got this from Lidia's Italy but made some changes. The original recipe uses ground turkey, no carrots or celery. I spiced it up a bit and use what ever veggies I have on hand and lots of them. I was surprised how much my family enjoyed this and it changes every time I make it.
1Heat oven to 350. Pour 1 tbs olive oil into a large skillet, heat to medium hot
Chop all your vegetables into small cubes Except potatoes. Cook, add salt to taste, don't brown just soften-remove to a bowl
2In another bowl combine your beef and sausage and put in pan with another tbs of oil if needed. Cook through, breaking up the meat and pour off the grease. Toast the tomato paste, and then stir it into the meat mixture. Add the vegetables. Combine. Stir in the wine or broth and simmer until mostly evaporated.
3Oil a 10 x 15 pan, toss potatoes in 1 tbs oil and layer in bottom of pan. Sprinkle the cheeses. Layer the meat and vegetable mixture thinly and sprinkle more cheese. Put final layer of meat and vegetables and cheese again. Cover with foil being sure the top is tented so the cheese doesn't stick. Bake for 20 minutes, remove foil and bake for 10 more minutes until cheese browns.