Peel the cucumber, halve it lengthwise, scoop out the seeds with a spoon, slice thinly, and layer in a dish. Sprinkle generously with coarse salt and let drain for 1 hour to release excess moisture.
In a bowl, whisk the cream to a soft, airy consistency (stop before it stiffens like whipped cream). Season with salt and pepper, then gently fold in the chopped chervil using a spatula.
Brush the puff pastry rectangles with beaten egg and bake in a preheated oven at thermostat 6 (200°C) for 15 minutes. Let cool completely.
Rinse the cucumber slices under cold water, drain thoroughly, and pat dry with paper towels. Fold into the chervil cream.
Spoon the mixture generously into the cooled puff pastries, allowing it to overflow slightly, and garnish with chervil sprigs.
Pro tip from the kitchen: Swap cucumber for cooked beetroot for a vibrant twist on this classic.
Joëlle's take: Ideal for balmy summer days and relaxed country gatherings—light, fresh, and effortlessly elegant.
