Prepare the shrimp by making a shallow slit at the back to butterfly them.
Set up your workspace with separate bowls for beaten egg, potato starch, and a large plate for holding the coated shrimp.
Dip each shrimp into the egg, then coat it evenly in tapioca starch before placing it on the plate.
Heat oil in a high-walled stainless steel or cast iron pan over medium-high heat.
Test the temperature after three minutes using a wooden chopstick; if bubbles form around it, the oil is ready, or use a thermometer to reach 350°F (177°C).
Fry the shrimp in batches for about three minutes per side until golden brown.
Remove and place on a wire rack to keep them crisp and drain excess oil.
In a bowl, mix mayo, honey, and milk until smooth to create the sauce.
Coat the walnuts in two tablespoons of the sauce and toss well.
Arrange the shrimp on a serving plate, top with the sweetened walnuts, drizzle with additional sauce, and garnish with scallions.
Serve immediately while hot.