1 brown onion, sliced and separated into 2cm rings
1 cup plain flour + extra for dusting
1 ½ tsp baking powder
Pinch cayenne pepper
125ml beer (may need a little more)
Vegetable oil, for deep-frying
Heat the oil in a large pot, wok or deep fryer to 180°C.
In a large bowl whisk together the flour, baking powder, salt and cayenne pepper. Make a well in the centre and start pouring in the beer, gently whisking constantly. The consistency should be like that of thickened cream, or a little thicker than pancake batter.
Place the onion rings in the batter, shake excess off and then gently lower into hot oil. Cook until golden brown and very crispy.
Drain on a rack or some paper towel and season again with a little salt and vinegar.