Slice the Camembert. Cut the Camembert horizontally through the middle so you have two equal rounds.
Add the filling. Spread the roughly chopped walnuts over one half of the Camembert and the chopped dried cranberries over the other. Gently press the cranberries into the cheese with your hand so they stay in place.
Close the Camembert. Place the cranberry-covered half back on top of the walnut-covered half to re-form the wheel.
Wrap in puff pastry. Unfold the puff pastry and roll it lightly with a rolling pin so it is just slightly thinner. Place the stuffed Camembert in the center. Fold the pastry around the cheese, completely enclosing it, and trim away the excess pastry.
Decorate. Use the leftover puff pastry to decorate the top if desired. I created a small bunch of grapes from pastry circles, but leaves, vines or other shapes work beautifully.
Add the egg wash. Beat the egg with 2 teaspoons of water. Brush the egg wash over the entire surface of the puff pastry.
Freeze. Place the wrapped Camembert in the freezer for 1 hour. After about 50 minutes, preheat the oven to 425°F (220°C).
Bake. Place the chilled Camembert on a parchment-lined baking sheet. Bake for 20 to 25 minutes, until the puff pastry is beautifully puffed and golden brown. A little cheese beginning to escape from the pastry is a good indication that the Camembert inside is melted.
Serve warm. Allow it to rest for a few minutes before serving with sliced baguette, crusty bread, grapes, apples, pears or figs.