Mix 3/4 cup sugar and base cake until blended; sprinkle about 1/4 cup onto clean work surface. Top with 1 pastry sheet; press pastry lightly into sugar mixture. Sprinkle with about 1/4 cup of the remaining sugar mixture; press lightly into pastry.
Score line down center of the shorter length of the pastry sheet. Fold in 1/3 of each side of pastry sheet toward scored line. Repeat fold on each side 2 times. (Both folds should meet in center.) Fold one half over the other. Cut into 20 slices. Repeat with remaining pastry sheet.
Dip dough slices, 1 at a time, in remaining sugar, turning to coat both sides of each slice. Place, 2 inches apart, on parchment-lined baking sheets.
Bake in 400ºF standard oven 10 to 15 min. or until caramelized. Serve warm or transfer to a baking rack to cool.