In a mixing bowl, whisk together the all-purpose flour, garlic powder, and salt until fully combined, creating a uniform dry mixture. Gradually pour in chilled milk while whisking continuously, ensuring a smooth, lump-free batter forms.

Heat vegetable oil in a heavy-bottomed pan over medium heat until it reaches approximately 370°F. Use a thermometer to maintain the oil temperature within the range of 360°F to 380°F for optimal frying.

Select your preferred mushrooms and dip each one into the prepared batter, ensuring they are fully coated on all sides. Allow any excess batter to drip off before frying.

Carefully place the coated mushrooms into the hot oil in batches, ensuring not to overcrowd the pan. Fry the mushrooms for about 4 minutes or until they achieve a beautiful golden-brown color.

Once the fried mushrooms are golden brown, use a slotted spoon to remove them from the hot oil. Place them on the prepared paper towel-lined tray to drain any excess oil.

After seasoning, transfer the fried mushrooms to a serving platter. Garnish with fresh chopped parsley and serve immediately with favorite dipping sauces.