1. Prepare the Beef Filling: Heat olive oil in a large skillet over medium heat. Add ground beef and cook, breaking it apart with a spoon, until browned. Drain any excess fat.n2. Sauté Aromatics: Add chopped onion to the skillet and cook until softened, about 3-5 minutes. Stir in minced garlic, dried thyme, dried rosemary, salt, and black pepper. Cook for another minute until fragrant.n3. Thicken the Filling: Sprinkle flour over the beef mixture and stir well to coat. Cook for 1 minute. Gradually pour in beef broth, stirring constantly until the mixture thickens slightly. Remove from heat.n4. Add Cheese: Stir in the shredded cheddar cheese until melted and fully incorporated into the beef mixture. Allow the filling to cool slightly.n5. Prepare Puff Pastry: Preheat your oven to 400°F (200°C). Line two baking sheets with parchment paper. On a lightly floured surface, gently unfold one sheet of thawed puff pastry. Roll it out slightly, just enough to even out any creases.n6. Cut Tree Shapes: Using a Christmas tree-shaped cookie cutter (approximately 3-4 inches tall), cut out as many tree shapes as possible from the first puff pastry sheet. Repeat with the second sheet. You should have 12-16 tree shapes in total.n7. Assemble the Trees: Place half of the puff pastry tree shapes onto the prepared baking sheets. Spoon about 1-2 tablespoons of the cooled beef and cheese filling onto the center of each tree shape, leaving a small border around the edges.n8. Top and Seal: Place the remaining puff pastry tree shapes on top of the filled trees, aligning the edges as best as possible. Gently press down around the edges to seal the two layers of pastry together, ensuring the filling is enclosed. You can use the tines of a fork to crimp the edges for a decorative seal.n9. Egg Wash and Bake: Brush the tops of the assembled Christmas trees with the beaten egg wash. This will give them a beautiful golden-brown finish. If desired, use a small star-shaped cookie cutter to cut out small stars from any leftover pastry scraps and place them on top of your trees before egg washing for an extra festive touch.n10. Bake: Bake for 15-20 minutes, or until the puff pastry is golden brown and puffed up.n11. Garnish and Serve: Carefully transfer the baked Christmas trees to a wire rack to cool slightly. Garnish with fresh chopped parsley if desired. Serve warm.