To prepare the pastry, start by placing the flour and salt in a bowl. Add the cold, diced butter and mix until you have a crumbly texture. Add the cold water and quickly knead the dough until it comes together. Form the dough into a ball, wrap it in cling film, and refrigerate for 30 minutes.

While the pastry is chilling, prepare the filling ingredients. Slice the asparagus into thin rounds, leaving the tips whole. If using frozen peas, remove them from the freezer. Boil the quail eggs for about 4 minutes, then peel and cut them in half. In a bowl, whisk together the eggs, cream, thyme, and salt.

Roll out the chilled pastry on a lightly floured surface until it’s about 3-4 mm thick. Use the pastry to line 8 small tartlet tins, pressing it firmly into the sides and bottom. Chill the tartlet tins in the refrigerator for about 15 minutes.

Bake the pastry crust with weight (line the prepared crust gently with baking paper and fill it with ceramic balls or dried beans/peas) for about 15 minutes. Remove the paper and the weight, then continue to bake for an additional 5 minutes or until the pastry is golden brown.

Once the pastry bases have cooled slightly, fill each one with the sliced asparagus, green peas, quail egg halves, and grated Gruyere cheese. Pour the egg and cream mixture over the top of each tartlet. Bake the tartlets for about 15 minutes. Serve warm or at room temperature. Enjoy!