In a large frying pan, heat 1 tablespoon of olive oil over medium-high heat. Sear the lamb shanks in batches for about 6-8 minutes until they develop a rich, golden-brown crust on all sides. Transfer the shanks to a plate and set aside.

In the same pan, add another tablespoon of olive oil and reduce the heat to medium. Sauté the chopped brown onion for 3-4 minutes until softened. Stir in the middle bacon for another 3-5 minutes until crispy.

Sprinkle the plain flour into the onion and bacon mixture, stirring for about 1 minute to toast it. Add in the tomato paste, minced garlic, and paprika, mixing for another minute until fragrant.

Transfer the onion mixture into your slow cooker. Pour in the chicken stock, adding sliced mushrooms next. Gently place the browned lamb shanks on top, seasoning generously with sea salt and black pepper.

Cover the slow cooker and set it to HIGH for 4 hours or LOW for 8 hours until the lamb is fork-tender.

Once tender, carefully remove the shanks and place them on a serving dish. Stir in the sour cream into the sauce until smooth and creamy. Serve over cooked pappardelle, topped with extra sour cream and parsley.