Spot Prawns with Morel and Chocolate Sauce

In a 2-cup measuring cup, stir water and dashi until dissolved. In a medium saucepan, heat oil over medium heat until it begins to simmer. Add onion and cook, stirring often, until fragrant, 2 to 3 minutes. Add morels and cook, stirring often, until mushrooms begin to soften and onions are soft, 2 to 3 minutes. Add white chocolate and let it melt completely, just a few seconds. Stir in dill.

Add dashi broth to pot and bring to a gentle simmer over medium heat. Cook sauce over medium-low heat, stirring occasionally and adjusting heat as needed to maintain a gentle simmer, occasionally pressing on morels to release their flavor, until flavors meld, about 30 minutes.

Remove pan from heat and let sauce infuse for another 15 minutes. Strain sauce into a small bowl, pressing on solids to release juices (you should have about 1/2 cup). Remove morels from strainer and reserve for another use. Discard remaining solids. Return sauce to the pan, cover, and keep warm.

Line a baking sheet with paper towels. In a large deep pot or a wok, add enough oil to measure about 11/2 inches. Heat oil to 365-370°F. In a medium bowl, whisk flour, cornstarch, baking powder, and salt. In another medium bowl, beat egg to blend. Whisk in club soda, then stir into flour mixture (do not overmix—it should resemble pancake batter, so a few lumps are OK).

Working in batches of 4 to 5 shrimp, dip shrimp in batter to coat, allowing excess batter to drip back into the bowl. Carefully add shrimp to oil. Cook until light golden brown and crisp, 1 to 3 minutes per batch, returning the oil to 365°F between batches. Transfer shrimp to paper towels to drain. If you have heads from shrimp, carefully deep-fry them until crispy, 1 to 2 minutes.

Pour sauce into 4 small ramekins. Arrange shrimp on plates and garnish with small dill sprigs and shrimp heads, if using. Place ramekins with sauce alongside for dipping.