Cook fettuccine in a large saucepan of lightly salted, boiling water following packet instructions. Drain and return to saucepan along with butter. Keep warm.
Meanwhile, heat 1 tablespoon oil in a medium frying pan and add onion. Cook for 5 minutes on medium heat until golden and translucent. Add garlic and paprika and cook for 1 minute or until fragrant. Transfer to a large bowl. Add 1 additional tablespoon oil to pan and heat. Add mushrooms and 2 tablespoons water. Cook until brown and tender. Remove from pan.
Add remaining oil to pan and add pork. Cook over high heat until pork is browned. Return onion and mushroom mixture to pan.
Add pizza sauce, soy sauce, stock powder and 1/4 cup water. Cook while stirring for 2 minutes or until heated through. Stir through sour cream and serve with fettuccine.