Clean the mushrooms by wiping them with a wet paper towel. Set aside.
In a large bowl, whisk together the flour with the spices: Adobo, black pepper, and salt. Mix in the cornstarch and baking powder. Slowly add in the water and stir to combine.
In a separate bowl, pour in the Panko breadcrumbs.
Dip each mushroom into the wet flour batter, allowing the excess to drip off. Then toss in the dry breadcrumbs. Place on a plate until ready to fry.
Heat about an inch of oil in a large, deep skillet over medium-high heat (adjusting heat as needed).
Fry about six mushrooms at a time for 2-3 minutes per side, until golden-brown all over.
Remove from the pan with tongs or a slotted spoon, and place on a plate lined with paper towels or a baking rack to drain the excess oil.
Be sure to let these cool down for about 5 minutes before biting into one, as the middle can still be quite hot.
