Whelks with Parsley and Garlic Butter

Whelks with Parsley and Garlic Butter 1 ounce garlic (about 7 cloves, germ (the green sprout) removed)1 ½ ounces flat-leaf parsley (about 1/2 bunch, heavy stems removed)8 ounces 2 sticks soft unsalted butterSalt¼ teaspoon ground black pepperPinch cayenne1 pound whelks...