Wash the broccoli florets thoroughly and pat dry. Cut into small, bite-sized pieces, about 2-3 cm each, ensuring they are dry to prevent splattering during frying.
In a large mixing bowl, whisk together the all-purpose flour, cornstarch, baking powder, and salt until well combined. Pour in the cold water and add the beaten egg, stirring until the batter is smooth and slightly thick, with no lumps.
Dip each broccoli floret into the batter, coating it evenly. For an extra crispy crust, re-dip the coated floret into the batter before frying, allowing excess to drip off gently.
Heat oil in your deep-frying pan or pot to 180°C (350°F). To test if the oil is ready, drop a small piece of batter—if it sizzles and rises to the surface immediately, you're good to go.
Carefully lower the battered broccoli into the hot oil in small batches, making sure not to overcrowd the pan. Fry for about 3-4 minutes, turning occasionally, until the bites turn deep golden brown and emit a smoky aroma.
Use a slotted spoon to remove the crispy bites from the oil, then transfer them onto a wire rack or paper towels to drain excess oil and keep their crunch.
While frying the remaining batches, sprinkle the cooked bites with a little flaky sea salt if desired and squeeze fresh lemon juice over them for a bright finish.
Serve immediately while hot and crispy. These bites are best enjoyed fresh, but can be kept warm in a low oven for a few minutes if needed. Pair with your favorite dipping sauce for extra flavor.
