Cook the vegetables in salted water until soft, drain thoroughly and set aside on kitchen paper so all excess moisture is removed.
Mix the cooked and drained vegetables with the béchamel sauce and parsley.
Spoon into the bottom of the deep pan plate on your Evolve grill.
Add the flour to a blender and add the butter, blend until a crumb is formed (alternatively, cut very cold butter into small chunks and rub into the flour using your fingers to achieve the same result). Add the parmesan.
Top the vegetables with the flour mix and attach to the grill. Cover the top with a piece of baking parchment and close the lid.
Heat the grill to 160ºC and cook for 15-25 minutes until heated all the way through and golden brown on top.