Bring 2 cups water to a rolling boil. Add walnut halves and boil for 6 minutes. The water turns dark brown as tannins extract from the skins. Drain. Taste a walnut. If it's still astringent, repeat with fresh water for 3 to 4 more minutes.

Combine sugar, corn syrup, water, salt, and tapioca starch in a small saucepan. Heat over medium until the syrup reaches 240°F (115°C). The syrup should look glassy and slightly thickened. Off heat, add the drained walnuts and toss thoroughly with a heatproof spatula until every walnut is fully coated.

Spread coated walnuts in a single layer on a parchment-lined baking sheet, separating any clumps. Place in a 200°F (95°C) oven for 15 to 20 minutes. The coating should look translucent and amber, sticky to the touch but no longer wet.

Heat 2 cups neutral oil to 350°F (177°C) in a small heavy saucepan. Fry the walnuts in two batches for 2 to 3 minutes each. Watch the bubbles: they start large, then transition to small and gentle as residual water leaves. The coating darkens to deep amber-gold. Remove with a slotted spoon to a wire rack and immediately separate any pieces that touch. Cool fully, 10 to 15 minutes. The coating hardens into a glassy candy shell as it cools.

In a medium bowl, whisk sugar and xanthan gum together until evenly combined. Add evaporated milk, oil, distilled vinegar, malic acid, salt, MSG, and honey. Grate the salted egg yolk half directly into the mixture using a microplane. Whisk vigorously for 30 to 60 seconds. The sauce thickens slightly and turns pale yellow-cream as the egg yolk emulsifies. Set aside. Stir again before using if it sits more than 10 minutes.

In a medium bowl, whisk together all-purpose flour, tapioca starch, cornstarch, potato starch, rice flour, vital wheat gluten, nutritional yeast, salt, and baking powder. Add cold water and 1 tablespoon neutral oil. Whisk until smooth with no dry pockets. Rest 5 to 10 minutes. The finished batter should coat the back of a spoon without dripping off in sheets.

Pat shrimp very thoroughly dry with paper towels. Toss with 1/2 teaspoon salt. Set aside on a plate. Do not dredge yet. Dredge happens one at a time during the par-fry.

Heat 4 cups neutral oil to 350°F (177°C). Working in batches of 8 to 10 shrimp, dredge each shrimp in cornstarch, shake off excess, dip into the wet batter, let excess drip off briefly, then lower into the oil. Par-fry each batch for 90 seconds to 2 minutes. The batter sets and turns straw-yellow with light blistering. Remove to a wire rack.

Let the par-fried shrimp rest on the wire rack until completely cool to the touch, 20 to 30 minutes. Do not freeze hot shrimp. Condensation in the freezer softens the batter.

Transfer the cooled par-fried shrimp to the freezer for at least 4 hours, ideally overnight. The shrimp are ready when hard to the touch all the way through.

Heat oil to 375°F (190°C). Take half of the frozen par-fried shrimp from the freezer. Fry the entire half-batch all at once for 4 minutes. The crust shifts from straw-yellow to deep amber-gold. Remove to a clean wire rack. The remaining half holds in the freezer up to 2 weeks, double-bagged. Go from freezer straight to second fry with no thawing.

Heat a clean, dry wok over high heat for 1 to 2 minutes until lightly smoking. Do not add oil. Turn the heat off. Stir the sauce one final time to re-disperse the xanthan, then pour it into the hot wok. Turn the heat back on to medium. As soon as it reaches a full boil (15 to 30 seconds), turn the heat off immediately. Add the shrimp and toss continuously for 10 to 15 seconds, off-heat, until every piece is evenly coated and glossy. Transfer to a serving platter. Top with 1/4 cup of the candied walnuts. Do not toss the walnuts in. They go on top to stay crisp. Serve immediately.