Prepare the Batter: In a large bowl, whisk together the flour, cornstarch, baking powder, salt, and white pepper. Gradually add the cold water, stirring until a smooth batter forms.

Heat the Oil: In a deep skillet or wok, heat about 2 inches of vegetable oil to 350°F (175°C).

Fry the Cauliflower (First Fry): Dip the cauliflower florets into the batter, ensuring they are well-coated. Allow any excess batter to drip off.

Carefully place the battered florets into the hot oil in batches, avoiding overcrowding. Fry for 3-4 minutes until they are light golden brown. Transfer to a wire rack or paper towel-lined plate to drain.

Fry the Cauliflower (Second Fry): Once all florets have undergone the first fry, increase the oil temperature to 375°F (190°C).

Return the cauliflower to the hot oil in batches and fry for an additional 2-3 minutes until they achieve a deep golden brown and crispy texture. Drain as before.

Prepare the Soy Garlic Glaze: In a small saucepan over medium heat, combine the soy sauce, rice vinegar, sugar, water, minced garlic, and grated ginger. Bring the mixture to a simmer.

Stir in the cornstarch slurry and cook for 1-2 minutes until the sauce thickens. Remove from heat and stir in the sesame oil.

Coat the Cauliflower: Place the double-fried cauliflower florets in a large bowl. Pour the soy garlic glaze over them and toss gently to ensure even coating.

Serve: Transfer the glazed cauliflower to a serving dish. Garnish with toasted sesame seeds and sliced green onions. Serve immediately.