Peel the apples and cut them into small pieces. Mix them with the walnuts and cinnamon. Put them with the honey in a pot to saute. Once they're ready, turn off the stove.
Lay 1 sheet of puff pastry in an oven dish laid out with baking paper, leave the edges of the puff pastry to stick out a little.
Pour the now cooled mixture into it and bend the edges. Cut the 2nd sheet of puff pastry into strips 1/2″ (1 cm) wide, then arrange them in a grid pattern on top of the mixture.
If desired, smear the strips with egg yolk.
Bake the pie until pink in a 410°F (210 °C) oven.