Preheat the oven to 400 degrees. Spread the sliced almonds on a baking sheet and toast for 6 to 8 minutes, until lightly browned. Set aside.
Put the pears, coffee, brown sugar, and vanilla in a medium saucepan and bring to a boil. If not using coffee, add some of the sherry Boil gently, covered, until the pears are tender, 10 to 12 minutes. Transfer the pears to a bowl.
Boil the syrup to reduce it, if necessary, to about ¾ cup. Dissolve the potato or corn starch in a little cold water, add to the syrup, and return to a boil. Pour over the pears, add the sherry, and mix well. Cover and cool.
To serve, put a slice of pound cake in each of four dessert bowls, with a scoop of ice cream. Sit a pear on top, coat with the syrup, and garnish with the almonds, cocoa nibs or grated chocolate, and mint.