Spread pesto sauce on the 1st sheet of the puff pastry.
Add ham (cheese is optional if you like to add) and cover with the 2nd sheet of the puff pastry.
Cut out Xmas tree shape, mark the tree stem.
Make symmetric cuts, start with the stripes on the right side, from the bottom to top. Twist each strip clockwise on the right site and anti-clockwise on the left, so the tree has symmetric branches.
Spread with egg yolk for the shinny color once baked.