MAKE THE ARUGULA PESTO:
Blend all the ingredients for the arugula pesto until creamy. Reserve.
MAKE THE ORANGE CARAMEL SAUCE:
On a skillet, on medium heat, add the sugar, stir until it becomes light golden and the sugar has completely dissolved.
Add the orange juice and stir until the caramel crystals have dissolved.
Add the cornstarch slurry and remainder of the ingredients. Reserve.
MAKE THE PESTO CHRISTMAS TREE:
Place one sheet of the puff pastry on parchment paper then place it on a flat baking sheet.
Cut the puff pastry in the shape of a triangle.
Spread the pesto evenly on top of the triangle shape.
Cover the puff pastry with the second puff pastry sheet, cut the sides to form a triangle. Score the center to mark where the tree branches are going to be cut.
Cut the sides of the triangle then twist the ribbons three times.
Brush the mayo-ketchup mixture on top of the tree.
Put the tree in the oven for 15 to 18 minutes at 200C / 400F.
Serve it with the remainder of the pesto and the orange caramel sauce on the side.