Peel the aubergines and cut lengthwise into 1 cm thick slices. Soak in a bowl of salted water for 20 minutes.

Meanwhile, cut the buns in half and toast or bake them to make them crispy.

Peel the onion and cut into rings. You can fry them as you like or use them raw.

Wash the pepper tomato and spinach or rucula.

Remove the stems from the spinach if necessary.

Cut the peppers into strips and fry them.

Slice the tomato.

Remove the aubergines from the salt water and dry with a clean cloth. For the wet breading, mix the water, flour and mustard in a bowl.

Put the breadcrumbs and spices in a plate and mix.

Dredge each aubergine first in the wet breadcrumbs and then in the breadcrumbs. Repeat the process once if desired.

Excess cutlets can be frozen.

Heat enough frying oil in a pan and fry the cutlets in it.

Now top the sandwich as you like and enjoy.