Pre-heat oven to 200 degrees C

Combine the black rub ingredients in a bowl

Remove the base of the cauliflower so it sits flat in a baking tray. 

Drizzle the cauliflower with two tablespoons of olive oil before massaging the rub all over.

Roast the cauliflower in the oven for forty-five minutes to an hour or until a knife glides through the centre easily.

While the cauliflower is roasting, peel and slice the red onion in to eight wedges.

Combine the vinegar, sugar, salt and cumin seeds in a small jar and add the red onion to pickle. If you have a lid, put it on and shake. If not, simply stir and set aside until you are ready to assemble the tostaditas.

To make the purée, put the coriander, avocado, lime juice and salt in a food processor and process until smooth. Add a teaspoon of water to help if needed. 

When the cauliflower is cooked, break it up into small florets. I use a knife and slice downwards; the cauliflower tends to fall apart. 

To assemble, spoon a good dollop of the avocado purée on to the tosadita, followed by the black rub cauliflower. Finish with a smattering of the pickled onion and fresh coriander and a squeeze of lime.