Preheat oven to 375 degrees F. Lightly coat a 9-inch pie plate with cooking spray; set aside. For crust, in a medium bowl stir together crushed amaretti and ground almonds. Drizzle with1/3 cup melted butter; toss gently to combine. Press evenly onto the bottom and up the sides of the prepared pie plate.
For filling, in a large mixing bowl beat cream cheese with an electric mixer on medium speed for 30 seconds. Add 1/2 cup sugar and almond extract. Beat until fluffy, scraping sides of bowl occasionally. Beat in half-and-half; stir in eggs just until combined. Pour filling into crust, spreading evenly. Cover edge of pie loosely with foil. Bake for 30 to 35 minutes or just until center is set. Cool on a wire rack.
Meanwhile, if using frozen cherries, let stand at room temperature for 30 minutes (do not drain). For cherry topping, in a medium saucepan stir together 1/2 cup sugar and cornstarch. Stir in cherries and cherry juice. Cook and stir over medium heat until thickened and bubbly. Cook and stir for 2 minutes more; cool.
Spoon cherry topping on top of pie. Cover and chill for 4 to 24 hours. Before serving, sprinkle with sliced almonds and, if desired, white chocolate.