Thaw the pastry sheets at room temperature for 40 minutes or until they're easy to handle.
Unfold 1 pastry sheet onto a lightly floured surface.
Roll the pastry sheet into a 15x10-inch rectangle.
Cut the pastry rectangle lengthwise into 3 (5x10-inch) rectangles.
Brush the pastry rectangles with the egg. Repeat with the remaining pastry sheet.
Spread 1 tablespoon cream cheese on the bottom half of each pastry rectangle. Top each with about 3 slices ham,about 2 tablespoons arugula leaves and 2 slices nectarine. Fold the top halves over the filling and press the edges to seal.
Place each pastry packet one at a time into a panini maker and close the top. Cook for 6 minutes or until the panini is golden.
Remove the panini to a baking sheet and keep warm in a 275 degrees F. oven while the remaining paninis are cooked.
