Begin by rinsing your shrimp under cold water. Pat them dry with paper towels. This is crucial as excess moisture can prevent that lovely batter from adhering to the shrimp. Next, place the shrimp in a bowl and add a pinch of salt and pepper. Let them sit for a few minutes.

In another bowl, whisk together the egg whites and water until frothy. Gradually add the cornstarch while mixing until you obtain a smooth batter. It should be thick but not too heavy. When done, it’s time to coat those shrimp!

Dip each shrimp into the batter, ensuring it’s fully coated. Shake off any excess batter, as a little goes a long way. Place the battered shrimp on a plate lined with parchment paper while you heat the oil.

In a deep skillet or pot, heat vegetable oil over medium-high heat. You'll know it's ready when it shimmers and a drop of batter sizzles on contact. Don’t overcrowd the pan; fry in batches for even cooking.

Once the oil is hot, carefully add the shrimp in batches. Fry them for about 2-3 minutes on each side until they turn golden and crispy. Use a slotted spoon to remove them and drain them on paper towels.

In a separate pot over low heat, combine the granulated sugar, honey, mayonnaise, sweetened condensed milk, and rice vinegar. Stir continuously until the mixture is smooth and heated through. It shouldn’t boil; just a gentle warmth is enough to meld the flavors.

In a small pan, toast the walnut halves over medium heat until they’re golden brown. This enhances their flavor. Be sure to watch them closely as they can burn quickly.

In a bowl, toss the crispy shrimp with the sauce until they’re well-coated. Sprinkle in the toasted walnuts and gently fold them in. If desired, top with finely chopped scallions for added color and freshness.