Abruzzo is Italy's leading exporter of saffron, and more "exotic" ingredients like raisins and curry powder are definitely not unheard of there. Abruzzo was part of the Kingdom of Sicily historically, which came with many Islamic food influences from the time of the Moors. I brainstormed with those influences in mind to create a casserole that is both exciting and familiar comfort food.
Begin cooking the pasta while you are making the sauce. Be sure to use salted water and only cook to al dente because the pasta will also cook in the casserole. Don't forget to reserve 1/2 cup of the cooking water!
Preheat the oven to 375 F or 350 F convection.
Heat 2 tablespoons of the olive oil in a medium-large heavy skillet over medium high heat. When it is hot, add the onions with a pinch of salt.
Keeping the red wine nearby to deglaze the pan if the onions start to scorch or stick, let the onions cook, stirring occasionally, for 5 minutes.
Add the sweet bell pepper and garlic. Stir, and cook another 5 minutes.
Add the thyme and the mushrooms with another pinch of salt. Toss and cook, letting the mushrooms expel their water and start to brown, another 5 minutes. By now I definitely needed to deglaze with a few splashes of wine.
Add the curry powder and stir it in, letting it roast briefly, like 30 seconds. Then add the tomatoes and stir them in with the 1/2 teaspoon of salt (only add a pinch of salt if using canned tomatoes with salt).
Add the 1/2 cup red wine and let it boil off a little. You want it pretty loose because you do not want the casserole to dry out. Let it boil for about 3 minutes.
Transfer the sauce to a large bowl. Add 2 more tablespoons of olive oil to the pan and add the meatballs to the pan. Let them brown on 2 sides, about 5 minutes for the first side and 3 minutes for the second side.
While the meatballs are browning, add the raisins to the sauce and stir them in. Also add the saffron with its soaking water.
Remove the meatballs to a medium sized bowl.
Mix the cream into the cooler sauce.
Drain the pasta and mix it into the sauce, along with 1/2 cup of reserved pasta cooking water.
Note that everything through this point could be done the day before if you are pressed for time.
Very lightly oil a deep casserole dish. Add about 2/3 of the pasta-sauce mixture. Then layer the meatballs over that and add the rest of the sauce and pasta over the meatballs.
Sprinkle generously with the grated Pecorino Romano.
Cover with foil and bake for 20 mins (if you are starting with a cold casserole assembled the day before this stage will take longer, around 40 minutes).
Then uncover, sprinkle with more pecorino and bake for 15-20 more minutes (longer depending on how undercooked your meatballs were when they were added to the casserole; I slid a thermometer into one of mine and confirmed it was 165 F).
Let the casserole stand for 5-10 minutes if you have the time. Serve with even more grated pecorino over individual servings.