Bring a large pot of lightly salted water to a boil. Add pasta and cook for 7 to 9 minutes, until al dente.
Melt 90g butter with the olive oil in a large frypan over medium heat. Mix in the parsley and garlic and cook for a couple of minutes until fragrant. Add the mushrooms and asparagus and season with salt, pepper and onion powder; cook, stirring occasionally until asparagus is tender, about 5 minutes depending on the thickness.
Place the scallops in the pan and cook briefly on each side until lightly browned and the centre is cooked through, about 3 minutes per side. Remove from the heat when scallops are just finished.
Meanwhile, in a small saucepan,combine the milk, mascarpone cheese and 2 tablespoons butter. Cook over medium heat, stirring, until sauce is warm and butter is completely melted and blended in. Stir this sauce into the scallops and vegetables along with the pasta and serve immediately.