Peel and devein the shrimp, leaving the tails on if desired. Pat shrimp very dry with paper towels. Season lightly with 1 tsp fine sea salt and 1/2 tsp freshly ground black pepper. Lightly dust each shrimp in the 1/4 cup all-purpose flour, shaking off excess — this helps the batter adhere.

Make cold tempura batter

Place 1/2 cup all-purpose flour, 1/4 cup cornstarch and 1/2 tsp baking powder in a bowl and whisk to combine. If using the egg, lightly beat it and whisk into the dry mix. Add 3 ice cubes to the 3/4 cup ice cold sparkling water to chill it for 30 seconds, then remove the ice cubes. Pour the sparkling water into the dry mix and whisk quickly just until combined; small lumps are fine. Keep the batter very cold by placing the bowl in a larger bowl of ice or transferring to the refrigerator until ready. Cold batter + carbonated water yields a light, crispy texture.

Heat oil

In a heavy-bottomed pot or deep fryer, pour 3 cups of vegetable oil (enough for a 2–3 inch deep fry) and heat to 350°F (175°C). If you don't have a thermometer, test by dropping a small bit of batter — it should sizzle and float, browning in ~45–60 seconds.

Fry shrimp

Working in small batches (3–4 shrimp at a time so oil temperature holds), dredge dusted shrimp into the cold batter, letting excess drip off. Carefully lower into hot oil with tongs or a spider. Fry until the batter is pale golden and crisp, about 1.5–2.5 minutes depending on shrimp size. Avoid overcrowding. Use a slotted spoon to transfer fried shrimp to a paper towel–lined tray. Season immediately with a pinch of salt while hot. Keep finished shrimp warm in a single layer on a baking sheet in a 200°F (95°C) oven while you fry remaining batches.

Finish

When all shrimp are fried, give them a final light sprinkle of salt. Serve hot with lemon wedges and the spicy cream sauce on the side or tossed with sauce (see sauce directions).

Spicy Cream Sauce

Make the sauce: In a medium bowl, combine 1/2 cup mayonnaise, 3 tbsp heavy cream, 2 tbsp sriracha, 1 tsp tomato paste, 1/2 tsp soy sauce, 1 tbsp fresh lemon juice, 1 tsp honey, 1 tsp minced garlic, 1/2 tsp smoked paprika, 1/4 tsp kosher salt and 1/4 tsp freshly ground black pepper. Whisk until smooth and well blended. Taste and adjust heat (add more sriracha) or acidity (add a squeeze more lemon) as desired.

Thin or thicken: If the sauce is too thick for dipping, whisk in an additional teaspoon of heavy cream or 1–2 teaspoons of warm water to loosen. If you prefer a thicker glaze for tossing, chill the sauce 10–15 minutes so it firms slightly.

Serve options: For classic presentation, serve the fried shrimp alongside a small bowl of sauce for dipping. For 'Mama Mia Shrimp' tossed style, place fried shrimp in a large bowl, spoon 3–4 tbsp sauce over them and gently toss to coat evenly, then transfer to a serving platter and garnish with chopped chives or green onions.

Accompaniments (Optional)

Plate: Arrange 2 cups mixed greens or shredded cabbage on serving plates (optional) and mound the shrimp on top. Serve with steamed rice or crusty bread and lemon wedges. Sprinkle chopped chives or green onions over the sauced shrimp for color and aroma.