Preheat your oven to 200°C/180°C fan/400°F/Gas 6
Spiralise your courgettes using the coarse setting to give the thickest strings.
Mix spiralised courgette with salt in a colander and leave to one side to drain.
Slice red onions as thinly as you can. Make sure your onion slices are all roughly the same size.
Squeeze the excess water out of the courgettes before transferring to a large mixing bowl.
Mix the red onion slices in with the courgette.
Add spices and flours until the courgette and onion are evenly coated. You shouldn't need to add any water as the courgette will continue to ooze liquid even though you have already squeezed out excess water.
Add ½ tsp of oil to each muffin cup.
Evenly distribute the bhaji mixture into the muffin cups - about one heaped tablespoonful per cup. If you are using a lined baking sheet - pile up in 12 equal mounds.
Pop in the oven for 25 minutes, brushing your bhajis with oil halfway through baking.
Once cooked, leave to rest for 5 minutes before removing from the tin.