Heat 1/4 cup water in a small saucepan over medium heat and bring to a boil.
Add the white and brown sugars and stir constantly until the mixture becomes golden and thickened.
Stir in the cashews until they are evenly coated with the caramelized sugar, then transfer the nuts to a parchment-lined plate to cool and set.
In a small bowl, whisk together the mayonnaise, lemon juice, honey, and condensed milk until smooth; set aside.
Pat the shrimp dry with paper towels and season lightly with kosher salt and freshly ground black pepper.
Working one at a time, dip each shrimp into the beaten egg, then dredge in cornstarch, pressing gently so the cornstarch adheres; place on a paper towel–lined plate.
Heat the vegetable oil in a large skillet over medium-high heat until shimmering.
Fry the shrimp in batches (about 8–10 at a time) until golden-brown and crispy, about 1–2 minutes per side; transfer to a paper towel–lined plate to drain.
In a large bowl, combine the fried shrimp, cooled candied cashews, and the creamy honey sauce; toss gently to coat.
Serve immediately.
