Bring a large pan of water, at least 2 litres, to the boil. Season with the stock concentrate. Add the rice and return to the boil, cook for 5 minutes making sure it doesn’t catch on the bottom but don’t stir too much. Strain through a colander or sieve. Spread into a single layer on a baking tray or two and put in the freezer until completely frozen. At this point, you can bag up the rice in portions and keep stored in the freezer ready to pull out for a quick risotto at a later date. Remove 240g of the rice from the freezer and defrost.
Bring the stock to the boil and add the rice, continue to boil whilst stirring regularly until the stock has reduced by about ¾. Add the mascarpone and boil until you have a creamy consistency, finish with the parmesan, herbs and lemon. Check seasoning. If it becomes too stodgy and thick add a little more stock to loosen.
Break the asparagus spears by holding gently at each end and bending until it breaks at its tender point. At this point take all the tougher ends and juice them or blend with a little water and strain. Reserve the juice.
Slice the asparagus into rounds all the way up to leave a 2cm tip, slice the tip in half lengthwise.
Heat a pan wide enough to contain all of the asparaguses in a single layer then add the butter followed by the asparagus, season with a little salt and cook until the asparagus just about starts to roast. At this point add the asparagus stock and just enough chicken stock to cover the asparagus. Bring to the boil and cook until most of the liquid has reduced away and what is left forms an emulsion with the butter giving a nice glaze to the asparagus.
Heat the oven to 170c. Mix the flour and parmesan together and sprinkle a thin layer on to a parchment lined baking tray. Bake for around 5 minutes or until golden brown.
Alternatively, cook in the microwave in 20-second bursts.
Serve the risotto in a mound in the centre of a bowl and cover it completely with the asparagus. Finish with some of the broken baked parmesan.