Preheat the oven to 220C/425F and line a large baking tray with a silicone mat or baking parchment.
Add the milk, water, flour, garlic salt, celery salt, paprika, chilli flakes salt and pepper to a large bowl. Mix it all together until no lumps remain, then add the cauliflower florets.
Mix together to completely cover the florets. Use a slotted spoon to lift the florets out of the mixture, allowing the excess batter to drip off. Place the florets on the prepared baking tray, leaving a little room between each.
Place in the oven and cook for 20 minutes, turning once after 10 minutes.
Meanwhile, add all of the sauce ingredients into a saucepan, stir and bring to the boil. Allow to bubble for 5-10 minutes until the sauce reduces and thickens slightly (it will thicken more as it cools). Turn off the heat.
Place the wings in a large bowl and very carefully pour over the sticky sauce (be careful, it will VERY hot). Toss to combine, then serve topped with chopped spring onions (scallions) and chilli flakes.