1. To make the batter, sift the flour, baking powder, and salt into a large bowl. Make a well in the center, add ½ cup of the beer, and whisk, gradually adding the remaining beer. Let stand for 30 minutes.

2. To make the sauce, stir the stock, soy sauce, vinegar, ketchup, honey, and ginger in a small saucepan over low heat until the honey is melted. Stir in the dissolved cornstarch and bring to a simmer. Cook, stirring often, until just thickened. Set aside.

3. Preheat the oven to 200°F (95°C). Fill a wok halfway with oil. Heat to 350°F (180°C). Place the flour in a bowl. In batches, toss the chicken in the flour, then coat in the batter and add to the hot oil. Deep-fry about 3 minutes. Transfer the chicken to a baking sheet lined with paper towels and keep warm in the oven.

4. Pour all but 2 tbsp oil from the wok and return to high heat. Add the cashews and stir-fry for 30 seconds. Transfer to the baking sheet. Add the red pepper to the oil and stir-fry 2 minutes, or until crisp-tender. Add the scallions and pineapple and stir-fry for 1 minute.

5. Pour the sauce into the wok, add the chicken and stir until coated. Transfer to a serving platter, sprinkle with cashews, and serve hot.