Preheat oven to 350°F.
Using a rolling pin, roll out the first 2 sheet of puff pastry fusing together lengthwise with fingers onto a prepared baking sheet with parchment paper. Do the same for the second 2 puff pastry sheets and set those two aside on a separate baking sheet.
Spread the pesto sauce onto the first sheet of puff pastry that is on top of the baking sheet. Then add the second sheet of puff pastry on top like a sandwich.
Brush the entire surface with an eggwash, grate some cheese on top and then sprinkle sesame seeds, if desired.
If desired, to help you cut the shape of the Christmas tree, stencil out a triangle template, and lay it on top of the puff pastry.
Using a sharp knife or pizza cutter, cut out the Christmas tree shape making sure to cut a tree trunk at the bottom. You can lay the extra sections of puff pastry aside. If you want to cut a star or other shapes with cookie cutters to cook at the same time as the tree is cooking.
As for the branches of the tree, you can place a ruler down the center of the puff pastry as a guide if it’s easier.
Starting on one side, make horizontal slices through the two puff pastry layers into the sides of the Christmas tree being careful to stop before you reach the center of the tree.
Repeat the same process on the other side of the tree triangle being careful to stop before reaching the center of the tree leave about a 1 to 2 inch section down the middle of the tree that is not sliced.
Begin twisting the branches away from you. Press the edge of the branch firmly into the parchment paper to keep the branch from untwisting. Continue twisting the branches until both sides are completed.
Brush the entire pastry with the egg wash and extra sesame seeds.
Bake in the preheated oven until puffy and golden brown, about 20 minutes. Cool slightly before serving.
Garnish along the branches with the peppers and mozzarella pearls. You can gently slide the Christmas tree pastry on to a serving platter. Or lift the parchment paper off the baking tray and place on top of a serving platter.