Preheat the oven to 350 degrees F.
Spread the walnuts on a baking sheet and toast for 10 minutes.
Increase the oven to 400 degrees F.
Place the frozen pastries on a baking sheet lined with parchment paper. Bake until puffed, 20 to 25 minutes.
Meanwhile, in a bowl, add the strawberries, balsamic and maple syrup. Mix.
While the pastries are still hot, stuff with the cheese, and then top with walnuts, strawberries and some pepper. Serve hot.