Melt butter in a large skillet over medium-high heat; add garlic, and saute 2 to 3 minutes.
Whisk together whipping cream and next 6 ingredients. Add to skillet; cook, stirring constantly, 2 to 3 minutes or until thickened. Toss with pasta. Sprinkle with parsley, if desired.
Note: For testing purposes only, we used French's classic yellow mustard.