Cut the 12 inch by 12 inch dough square in half vertically, then in half horizontally to create four 6 inch by 6 inch squares. Use a ruler for precise measurements and clean cuts.

Transfer each square to your parchment lined baking sheet before shaping. This is crucial to prevent tearing the delicate braided structure later.

For each square, measure 2 to 3 inches from each bottom corner along the sides. Mark the center point at the top edge (3 inches from either side).

Using a sharp knife, cut from the bottom left mark up to the top center point. Then cut from the bottom right mark up to the top center point. Remove the triangular side pieces and set aside for another use.

Mark your chocolate guide down the center of the triangle. At the bottom (wide base), mark 3/4 inch wide. At the top (point), mark 1.5 inches wide. Connect these marks with lines to create a tapered guide.

Arrange your chocolate pieces or sticks down the marked guide. Use 2 to 3 chocolate sticks per tree. Press gently so the chocolate adheres to the dough without compressing the layers.

Starting from the center chocolate guide, cut diagonal strips at a 45 degree angle outward to the edges, spacing cuts about 3/4 inch apart. Make these first cuts all the same width.

Go back and cut each wider strip in half down the middle to create your final branch strips. Leave 1 to 1.5 inches uncut at the bottom for the trunk, and a small section uncut at the top. You should have 5 to 6 strips on each side.

At the base of the triangle, fold one bottom corner over the chocolate. Wrap the other bottom corner around it and tuck it underneath to create the tree trunk.

Starting at the bottom above the trunk, take one branch from the left side and fold it over the chocolate diagonally toward the right.

Take a branch from the right side and fold it over, crisscrossing the left branch. Continue alternating sides, working your way up the tree. Pull each branch snug but not too tight.

After all branches are crisscrossed, go back to each individual branch and give it a gentle twist. Two to three turns per branch creates beautiful texture and prevents unraveling.

Lightly mist the shaped trees with water to prevent surface drying during the long proof.

Cover loosely with plastic wrap or a clean kitchen towel. Proof at room temperature (68 to 75°F) for 6 to 12 hours. The trees are ready when they are puffy, jiggly when you gently shake the pan, and you can see distinct butter layers separating.

When trees are fully proofed, preheat your oven to 400°F. Make sure it is fully preheated before baking.

Whisk together the egg yolk and milk. Brush this egg wash gently and evenly over all exposed dough surfaces, getting into the crevices between branches.

Bake at 400°F for 20 minutes, rotating the baking sheet 180 degrees halfway through (at 10 minutes) for even browning. Trees are done when deep golden brown all over with visible melted chocolate.

Let cool on the baking sheet for 5 minutes, then transfer to a wire rack. Dust with powdered sugar while still slightly warm if desired.

Serve warm or at room temperature. These are best enjoyed the day they are baked.