Fill a large pot with lightly salted water and bring to a rolling boil. Stir in fettuccini and return to a boil. Cook pasta uncovered, stirring occasionally, until tender yet firm to the bite, 8 to 10 minutes. Stir asparagus into pot during last 5 minutes of cooking; drain and transfer to a large bowl.

Meanwhile, heat cream and butter in a medium saucepan over medium heat until it begins to bubble; stir in Parmesan, garlic powder, black pepper, and cayenne. Continue cooking until the mixture thickens, stirring occasionally. Stir in ham until heated through.