If using a flax egg, make it now (mix and let thicken 5–10 minutes).

In a large bowl, beat softened butter and sugar until light and fluffy, about 2–3 minutes.

Beat in the egg (or flax egg) and vanilla until combined.

Whisk together flour, almond meal (if using), baking powder, salt, and zest. Gradually add to the butter mixture and mix until a soft dough forms.

Wrap dough and chill in the fridge for 30–60 minutes — this makes rolling easier and helps the cookies keep their shape.

Preheat oven to 180°C / 350°F. Line two baking sheets with parchment paper.

Roll dough into walnut-sized balls (about 20–25 g each). Place them 2.5–3 cm (1 inch) apart on the baking sheet. Gently press a small thumb-sized well in the center of each ball (or use the back of a small spoon) to make room for jam.

Bake for 10–12 minutes, or until edges are just golden. Rotate sheets halfway through for even baking.

Let cookies cool on the pan for 5 minutes, then transfer to a wire rack. Once fully cool, fill each well with about 1/2 tsp jam.

Melt dark chocolate gently (in short bursts in the microwave or over a double boiler). Spoon into a small piping bag or a zip-top bag with a tiny corner snipped. Pipe a small smile on each cookie, or use a toothpick to draw the line. Let chocolate set.

Dust lightly with powdered sugar if desired. Serve warm or at room temperature.