With a hand or stand mixer, whip together the softened cream cheese with the Guinness, Worcestershire sauce, mustard, garlic powder and salt until smooth.
Add the shredded Irish cheddar cheese and blend on low until combined.
Fold in the chopped green onions with a spatula.
Place the dip in a bowl and cover. Refrigerate for two hours before serving.
Serve the Guinness cheddar dip with baked soft pretzels.