Knead the soft butter by hand until workable (soft enough to slice easily, but not greasy/melted).

Beat in powdered sugar and vanilla until light and well combined.

Sift the flour and corn flour together and fold in, in three additions, mixing just until combined.

Knead briefly by hand on a board until smooth. Roll out to 6-7mm thickness, cover with plastic, and chill ~30 minutes (dough is soft and a little sticky).

Preheat oven to 170°C.

Flour the work surface, flip dough onto it, and cut shapes with a floured cookie cutter. Place 2-3cm apart on a parchment-lined baking sheet.

Bake 7-10 minutes depending on cutter size, until slightly puffed with lightly golden edges.

Transfer immediately to a cooling rack so they don't keep browning on the hot pan.

Once cool, decorate with melted chocolate as desired; chill 15 minutes to set the chocolate before stacking and serving.