Slice the aubergines in moderately thick slices. Place them onto a tray in a single layer and sprinkle generously with salt. Flip and repeat on the other side. Let it rest for about 15 minutes. It will release some moisture. Dab it off lightly using a kitchen towel. Keep aside.
Chop the spinach in long stands. Slice the onion in thin slices. Finely chop the coriander and green chili/es. Keep aside.
Take a bog bowl. Place a big sieve onto it. Add the besan, turmeric powder,red chili powder, salt and baking soda. Sift it thoroughly. Break lumps using a spatula if needed.
Gradually add the water while mixing with a whisk. Mix until a smooth paste is formed. The consistency should neither be too runny, nor too thick. It should be somewhat thick like honey.
Set the oven to preheat (top and bottom rods) at 180℃. Prepare an oven dish by lining it with a parchment paper. Using a brush, spread a thin coating of olive oil all over the lined tray (onto the parchment paper).
Dip the aubergine slices one by one into the batter. Wipe off the excess batter leaving a thin and even layer onto the aubergine slices. Place them in a single layer onto the lined baking tray.
Coat the peppers with a thin layer of batter and place them onto the tray.
(If tray is full already, then bake in batches). Into the remaining batter, add the chopped onion, spinach, coriander and green chili. Squeeze juice of lime. Mix thoroughly. The vegetables should be coated with the batter but the consistency should not be runny. If your batter is too wet, add some more besan (and season with salt).
Place small amounts of batter into the lined (and greased) baking tray to form pakoras. Leave some space between each pakora.
Put the trays into the oven and bake on 180℃ for 30 minutes (in total).
After 10 minutes, take the tray out and brush with some olive oil. Put it back into the oven.
After another 10 minutes, take the tray out again and flip all the pakoras. Brush with olive oil on the other side as well and put it back into the oven.
After the final 10 minutes, take the pakoras out from the oven. If you are not serving them immediately, transfer them onto a wired rack to keep them crunchy.
