In a stand mixer bowl, combine flour, salt, and oil. Gradually pour in water while mixing until a firm dough forms. Knead for 5-7 minutes. Divide the dough into four portions, roll into a ball, cover with cling film, and allow it to rest for 30 minutes.
There are two ways you can prepare the filling.Option one: In a medium size bowl, combine the lamb, onion, chilli, parsley, coriander powder, cumin powder, salt and black pepper until fully combined. Alternatively, you can cook the mixture: In a medium-sized pan, heat a couple of tablespoons of vegetable oil and fry the minced lamb until browned—season with coriander powder, cumin powder, paprika, chilli powder, salt, and black pepper. Remove from heat, let the mixture slightly cool, and then mix in the onions and parsley.
Parcook the split peas, then incorporate them with enough water to cover them. Bring to a boil, then reduce to a medium simmer, cooking until the peas are tender, approximately 20-25 minutes. Drain and set aside.
In a saucepan, heat oil over medium heat. Sauté onions until translucent. Add minced garlic and fry until fragrant. Stir in the tomato paste, vinegar, turmeric powder, coriander powder, cumin powder, chilli pepper, and black pepper. Add the cooked split peas and a cup of water. Allow it to simmer for an additional 15 minutes until the excess liquid reduces.
Roll the dough ball thinly on a floured surface. Slice into 2-inch squares. Spoon the meat mixture onto each square, fold by connecting opposite corners, seal the edges, and fold the sides.
Oil the steamer basket base. Arrange dumplings without touching each other. Steam for 15 to 20 minutes or until cooked through.
Mix yoghurt, labneh, lemon juice, zest, garlic, dill, and mint to prepare the yoghurt mixture in a bowl. Season to taste and set aside.
To serve, arrange the steamed mantu on a serving platter. Pour the tomato and spil pea sauce over the mantu and drizzle the yogurt sauce on top. Garnish with ground paprika and chopped fresh coriander or parsley.