In a medium-sized bowl, place 2-1/2 cups of the blueberries; stir in sugar and sherry; with a fork, mash about one-third of the blueberries. In another bowl, whip cream and confectioners sugar; set aside. Cut pound cake in 1-inch cubes. Prepare pudding as directed, using only 1-1/4 cups milk; place plastic wrap or waxed paper directly on pudding. Stir vanilla into cooled pudding; fold in half of the sweetened whipped cream. In eight parfait or wine glasses, or dessert bowls, arrange alternate layers of cake cubes, sugared blueberries and pudding, repeating twice. Cover loosely with plastic wrap; chill. Just before serving, top with remaining whipped cream and blueberries. Sprinkle with toasted sliced almonds and top with mint leaves, if desired.