First make the tostaditas, these can be done a few hours before. Place the small corn tortillas on a baking tray, add a bit of sunflower oil and bake in a pre-heat oven to 180 C, 350F, gas mark 4 for 15 minutes, turn them upside down, half way through. Once hard and golden brown, take them out and set aside.
Then make the coriander dressing. Place the fresh coriander in a blender and add the Onken natural yogurt and salt. Blend until smooth and set aside in the fridge until ready to serve.
Clean and deveined the prawns. Place them in a bowl and add the ground chilli powder, salt and pinch of black pepper, this step can be done in advance and then keep them in the fridge, ready to be fry just before serving.
When ready to serve, fry the prawns. Heat a frying pan to medium heat and add the vegetable oil. Then add the prawns and fry on one side for 2 minutes and flip them to fry the other side for another two minutes.
If using cauliflower florets instead of prawns place them on a baking tray and roast them in the oven to 180 C, gas mark 4, 350 F for 15 minutes.
To serve, simply spread some mashed avocado over a corn tostadita, place some prawn on top, then add some coriander yogurt dressing and scatter some fresh coriander leaves.