In a large Dutch oven, heat the olive oil (2 turns of the pan) over medium-high heat. Add the fennel seeds and stir for 30 seconds. Add the lamb, red pepper flakes and some salt and pepper and cook, breaking the meat into crumbles as it browns. Add the rosemary, thyme, onions, carrots, garlic, oregano, bay leaf, orange zest strip and cinnamon stick. Cook, stirring occasionally, until the onions soften, 7 to 8 minutes. Add the milk and reduce the heat to low. Simmer, partially covered, to let the meat absorb the milk, about 15 minutes.
Add the tomato paste and stir until fragrant, 1 to 2 minutes. Stir in the wine, partially cover, and continue to cook and reduce for 15 minutes. Add the stock and olives. Hand crush the tomatoes into the pot, then add the juices from the can. Simmer, partially covered, for 30 minutes more to cook down the tomatoes and thicken the sauce. Fish out and discard the orange zest strip, bay leaf and cinnamon stick. Adjust the seasoning.
Meanwhile, bring a large pot of salted water to a boil. Add the pasta and cook until al dente. Reserve 1 cup of the cooking water and drain the pasta. Keep warm.
Mix the mint, parsley, pistachios and some grated orange zest together in a small bowl.
Toss the ragu, reserved cooking water, pecorino, olive oil and cooked pasta together. Serve in bowls topped with fresh ricotta and sprinkle the herb-pistachio mixture over the top to garnish.