Preheat oven to 400 degrees Fahrenheit. Slightly roll out your puff pastry sheet. Use flour as needed. Using a sharp knife, cut pastry into 12 equal pieces. Prick squares with a fork, to reduce pastry rising too much in oven. Place on parchment lined baking sheet.
Brush pastry with egg wash (use your 1 egg whisked with a touch of water!) Top with chopped dill. Place in oven for 10-12 minutes until slightly golden. In the meantime, mix sour cream and cream cheese together until well incorporated. Season with salt and pepper.
Remove from oven and let cool, 4-5 minutes.
Top with a dollop of cream mixture, a piece of the smoked salmon and a sprig of dill. Serve immediately.
You'll want to make sure your puff pastry is thawed before using, but not out at room temperature for too long! I suggest keeping it in the fridge until ready to use!