Rinse the basil leaves and press lightly with a kitchel towel to remove surface moisture (to prevent oil spatter during frying). Set aside.
Tear larger mushrooms into two to three portions.
Add the beaten egg and toss until every piece is moist.
Add half a cup of starch and toss to distribute evenly. If still too wet, toss in the rest.
In a wok, heat enough cooking oil to reach a depth of at least three inches.
Over medium-high heat, fry the mushrooms in batches for two to three minutes per batch, until golden and crisp.
Scoop out the mushrooms and transfer to a strainer.
Reheat the oil and dump in the basil leaves. Cook for 45 seconds to a minute over medium heat or until the leaves acquire a subtle transparent appearance.
Scoop out and dump on a strainer.
Transfer the fried mushrooms and basil into a mixing bowl and toss lightly to distribute the greens.
Pile the crispy mushrooms and basil in a shallow bowl and sprinkle with your preferred seasoning.