PLACE mushrooms, onion and garlic in a food processor; cover. Process until slightly pasty. Pour into a large bowl. Add breadcrumbs and egg; mix until fully combined. Form into tablespoon-sized balls.
PREPARE pasta according to package directions; drain, reserving ¼ cup cooking water.
HEAT oil in a large skillet over medium heat. Add meatballs; cook for 2 ½ to 3 minutes per side. Remove from skillet; drain on a paper towel-lined plate. Discard any leftover oil. Increase heat to medium-high. Add wine; cook for 2 minutes.
REMOVE from heat; whisk in Alfredo sauce and 2 tablespoons reserved cooking water. Add pasta; toss to coat. Serve pasta topped with meatballs. Sprinkle with chopped fresh parsley, if desired.
