Place the butter, sugar and lemon zest in a stand mixer, and using the whisk attachment whip them until creamy and lightly foamy, for about 3-4 minutes.
Add one egg yolk at a time, until each is fully incorporated, followed by the whole egg. Continue to mix until you reach a creamy texture, for about 2 minutes.
Add in all the flour, and then mix everything with the hook attachment or by hand with a spatula.
The dough will still be sticky at this point, dust it with 1 tablespoon of flour and form the dough into a ball without over-working it.
Transfer the ball onto a sheet of cling film, flatten it into a disk and wrap it well. Let the dough rest in the refrigerator for at least 1 hour.
Once ready, transfer the dough on a clean and lightly floured working surface. Dust the rolling pin lightly with flour and roll the dough to about 3–4 mm thick (around ⅛ inch) before cutting the rounds.
Cut the dough into rounds about 5–7 cm (2–2.7 inches) wide. Place a spoonful of pears in the center. Fold the cookie over the filling to form a half-moon shape, trim off any excess pastry from the sides, then gently roll it between your hands until you have a neat ball.
Arrange the cookies on a baking tray lined with parchment paper. Bake in a preheated oven at 180°C (350°F) for 15–18 minutes, or until lightly golden at the edges.
Let the cookies cool on a wire rack, then dust with powdered sugar before serving.