Blue cheese and toasted walnuts are one of those amazing culinary matches, but here the richness goes one step further. There's a splash of sherry and a generous amount of softened butter in this cheese spread. Freeze it for up to a month in advance.
Stir together first 5 ingredients and, if desired, sherry in a large bowl; cover and chill mixture 8 hours. Let stand at room temperature to soften; or freeze spread up to 1 month, and thaw in the refrigerator for 8 hours.
Hollow out bread loaf, leaving a 1-inch-thick shell; reserve inside of loaf for other uses. Spoon softened cheese spread into shell. Garnish, if desired. Serve with sliced apples and pears or with toasted French baguette slices.