To prepare the orange balsamic:
Cut the vanilla pod in half lengthways and scrape out the seeds. Grate the outer peel of one orange. Cut all 3 oranges in half and squeeze in the juice (save the remainder of the orange for cubes to garnish).
Place the juice in a saucepan with the vanilla seeds, pod and grated peel. Add the water and sugar and bring to the boil.
Reduce the heat and keep simmering until the liquid is reduced by about half, then add 3 tablespoons of balsamic vinegar and continue to reduce until the consistency is like syrup. Serve while still warm.
To prepare the asparagus:
Remove the little points from the asparagus stems with a sharp knife and trim off the woody bases.
Tie the asparagus spears in a bundle with string so they are all facing the same way. Take a large pan and add the water and a good handful of salt. Taste the solution make sure it is quite salty. Bring the water to the boil, then plunge the asparagus into the pan and cook for 6-7 minutes until tender.
Check that the asparagus is cooked by gently piercing a stem with a knife. If the knife enters gently, the asparagus is ready; if there is still resistance, leave it in the water for another minute.
Remove the asparagus, take off the string and put the spears on a plate.
You can either serve the asparagus stems whole, or cut them in half lengthways.
Place them on the plate and add cubes of orange, a handful of spinach and parsley, and drizzle with the orange balsamic.