Preheat your oven to 180°C (350°F).
In a saucepan, bring water and butter to a boil.
Add flour all at once and stir vigorously until a smooth dough ball forms.
Let the mixture cool slightly, then add eggs one at a time, mixing thoroughly after each addition.
Line a baking sheet with parchment paper and shape the dough into a 25 cm circle on the sheet.
Bake for about 25 minutes until golden brown and puffed.
Let the pastry cool completely on a wire rack.
Mash avocados in a bowl and season with salt, pepper, and chopped chives.
Cut the cooled pastry ring horizontally, spreading avocado cream on the bottom half.
Layer slices of Scottish salmon and dollops of fresh cheese on top, then place the top half of the pastry back on.
