Heat the oven to 180°C/160℃ fan/350°F/gas mark 4 and line two baking sheets with baking paper.
Whisk the vegan butter, icing sugar, orange zest, orange extract and vanilla extract together until smooth.
Sift in the flour and cornflour and mix until well combined. The dough should be stiff but malleable and pipeable, like a stiff buttercream consistency.
Fit a piping bag with a large open star nozzle and spoon the dough into the bag. Pipe strips of dough onto the prepared baking sheets, well spaced apart as they will spread in the oven. Place the trays in the freezer for 15 minutes.
Bake the biscuits for 12-15 minutes until pale golden. Leave to cool on the sheet for 5 minutes then carefully transfer to a wire rack to cool (the biscuits are very delicate and break easily).
Melt the chocolate in a heatproof bowl set over a pan of simmering water, or in short bursts in the microwave. Transfer it to a narrow but deep container, such as a mug, to make it easier to dip the biscuits.
Dip either end of each biscuit in the chocolate, allowing any excess to drip back into the mug, then place them on sheets of baking paper until hardened before carefully peeling them off.