Preheat oven to 400F. Line a baking sheet with parchment paper.
Roll out the thawed puff pastry dough into a 10 inch by 12-inch rectangle (approximately). Make a half-inch border around the tart by folding the sides of the dough, using a fork to press down. Then use the fork to make dots throughout the middle of the tart and set aside.
In a bowl mix together the honey, melted butter, cinnamon, nutmeg and flour. Then toss the sliced pears in the mixture.
Line the pears on the pastry and drizzle with 3 tablespoons of the remaining honey mixture from the bowl.
Bake for 30-35 minutes or until the edges are dark golden brown.
Remove the oven and let cool on the baking sheet for 10-15 minutes. Sprinkle with walnut pieces before cutting and serving.