Cauliflower crust pizza

Name: Cauliflower crust pizza
Prep time: 15 min
Cook time: 45 min
Total time: 1 h
Cuisine: Italian
Ingredients: 1 cauliflower (about 750g/1lb 10oz); 100g ground almonds; 2 eggs beaten; 1 tbsp dried oregano; 227g can chopped tomatoes; 1 tbsp tomato purée; 1 garlic clove crushed; ½ large aubergine thinly sliced lengthways into long strips; 2 tbsp olive oil plus extra for greasing; 1 small red onion cut into 8 wedges; ½ small bunch basil leaves picked; 125g ball mozzarella; 25g Grana Padano or Parmesan (or vegetarian alternative), grated, plus extra to serve; a few pinches of chilli flakes