Step 1: Prepare the Candied Walnuts
1. Cook Walnuts: In a saucepan, combine the sugar and water. Bring to a boil over medium heat.
2. Add Walnuts: Add the walnuts to the boiling sugar mixture and cook for about 2-3 minutes, stirring frequently until the walnuts are coated.
3. Cool Walnuts: Remove the walnuts from the saucepan and spread them on a parchment-lined baking sheet. Let them cool and harden.

Step 2: Prepare the Shrimp
1. Mix Batter: In a bowl, combine cornstarch, flour, baking powder, salt, and pepper. Gradually whisk in the cold water until smooth.
2. Heat Oil: In a deep skillet or wok, heat oil over medium-high heat until hot (about 350°F or 175°C).
3. Coat Shrimp: Dip each shrimp into the batter, allowing excess to drip off.
4. Fry Shrimp: Fry the shrimp in batches for about 2-3 minutes, or until golden brown and crispy. Remove and place on a paper towel-lined plate to drain excess oil.

Step 3: Make the Honey Walnut Sauce
1. Combine Ingredients: In a separate bowl, mix together mayonnaise, honey, sweetened condensed milk, and lemon juice until smooth.

Step 4: Combine and Serve
1. Toss Shrimp: In a large bowl, gently toss the fried shrimp with the honey walnut sauce until well coated.
2. Add Walnuts: Top with the candied walnuts and serve immediately.