Cut a 1-inch layer from top of cake, remove and save.
Cut out center of remaining part of cake, leaving a 1-inch outside shell.
Fill bottom (to 1-inch depth) with pieces of cake you have removed from center.
Drain cherries; save syrup and heat it.
Dissolve gelatin in hot cherry syrup.
Remove from heat and add sherry.
Add vanilla ice cream, stirring until melted.
Chill until thickened but not set.
Fold one-half of the cherries into thickened gelatin mixture along with the 1/4 cup toasted slivered almonds.
Spoon into cake shell.
Replace cake top; refrigerate overnight.
Over very low heat, melt jelly; add grated orange peel and remaining cherries.
Stir carefully, just to glaze cherries.
Cool.
At serving time, fill cake center with glazed cherries.
Swirl sweetened whipped cream over top of cake, around cherry center; sprinkle with a ring of additional toasted, slivered almonds.