Rinse 1 lb Brussels sprouts under cold water. Trim the stem ends and remove any loose or discolored outer leaves. Cut each sprout in half lengthwise through the stem so the cut side is flat. Pat dry thoroughly with paper towels — minimal surface moisture helps achieve a crisp exterior.

Season

Place the halved sprouts in a bowl and toss with 1 tsp kosher salt and 1 tsp freshly ground black pepper. Let sit while you prepare the batter for 10–15 minutes (this draws out a little moisture and seasons the interior).

Breading & coating

Make the light batter

In a medium bowl whisk together 1 cup all-purpose flour, 2 tbsp cornstarch, 1/2 tsp baking powder, 1/2 tsp garlic powder, and 1/2 tsp paprika until evenly combined. Gradually whisk in 1 cup cold water until you have a smooth, slightly thick batter that will cling to the sprouts (a tempura-like consistency). Adjust with up to 1–2 tbsp more water if too thick; batter should coat but not be gloppy.

Coat the sprouts

Working in batches (do not overcrowd), hold each halved sprout by the stem and dip the cut side into the batter, allowing excess to drip off. Turn so both sides have a light coating. Place coated sprouts on a wire rack while you heat the oil. Reserve any remaining uncoated sprouts in the bowl lightly dusted with leftover flour mixture to prevent sticking.

Frying

Heat the oil

Pour 4 cups neutral oil into a deep, heavy-bottomed skillet or Dutch oven to a depth of about 1 to 1 1/2 inches. Heat over medium-high until the temperature reaches 350–365°F (175–185°C). If you don't have a thermometer, test by dropping a small bit of batter into the oil — it should sizzle and rise steadily.

Flash-fry in batches

Carefully lower a few batter-coated sprouts (cut side down first) into the hot oil so pieces have room to crisp; fry 6–8 halves at a time depending on pan size. Fry for 2 to 3 minutes, turning once with a slotted spoon or spider, until the coating is golden and crisp and sprouts are tender when pierced with a fork. Total frying per batch should be about 3–4 minutes. Do not overcrowd the pan or the oil temperature will drop.

Drain

Use a slotted spoon to transfer fried sprouts to a paper towel–lined baking sheet or wire rack placed over a sheet pan. Season immediately with a light pinch of salt if desired. Repeat with remaining sprouts, bringing oil back up to temperature between batches if needed.

Finishing & garnish

Finish

Once all batches are fried, place sprouts on a serving platter. While still hot, grate zest from 1 lemon over the sprouts and optionally squeeze 1–2 teaspoons of lemon juice for brightness. Sprinkle 1/4 cup grated Parmesan evenly, 1/2 tsp chili flakes, and 2 tbsp chopped fresh parsley. Toss gently to distribute the garnish without breaking the crisp coating.

Serve

Serve immediately while hot and crisp. Provide an optional dipping sauce (aioli or spicy mayo) on the side. Leftovers can be reheated in a 400°F oven for 5–7 minutes to re-crisp, but texture is best freshly fried.