Cut the onion into cubes and brown over low heat with 3 tablespoons of olive oil.
Add the potatoes and broad beans and continue toasting, always on low heat, for 2 minutes.
Add the water and bring to boil for about 15 minutes.
Add the asparagus cut into rings and continue boiling for another 10 minutes.
Turn off and let stand for 10 minutes. Sprinkle with chopped parsley.
In the meantime, turn on the oven at 180 degrees, take out the baking tray, arrange the croutons on a baking paper and topped them with a sprinkling of Parmigiano Reggiano.