Preheat oven to 200˚C, fan on.
Place portobellos on a baking tray. Spoon a little of the vinaigrette onto the mushrooms. Season with salt and pepper. Bake for about 10 minutes, depending on size, until tender and juicy.
While the mushrooms are baking, bring a pot of salted water to the boil. Prepare an ice bath and have it ready next to the stove.
Lower the asparagus into the boiling water.
Cook for about 1 minute, depending on the thickness of the stems.
Using tongs, remove the asparagus and plunge into ice water for a few minutes until cool.
Drain and dry the asparagus on a clean kitchen towel.
Using the same boiling water - add the 4 eggs gently, stir well to keep yolks in the center, and set a timer for 6.5 minutes.
Refresh the ice bath if necessary.
When the timer goes off, plunge the eggs immediately into the ice bath and leave them until cool enough to handle easily. Peel the eggs and set aside until serving.