Slice potatoes and onion into 1/8 - 1/4" slices. You can also cube your potatoes, either way is fine.

Place potatoes and onion on a piece of aluminum foil large enough to fold over and to be able to roll up edges. The heavy duty foil is best for this recipe.

Top potatoes with garlic, butter, Worcestershire and cayenne pepper.

Fold foil over to form a seam on top and roll edges to close.

Set grill to medium heat and cook for 30 minutes or in 350 degrees Fahrenheit oven (in a pan to avoid messes) for 35-40 minutes.

Check potatoes to make sure they are fork tender.

Cool slightly and serve.