Heat oven to 200C/180C fan/gas 6. Line a baking sheet with baking parchment. Tip the chickpeas, ½ tsp ground cumin, ½ tsp ground coriander, cayenne pepper, red onion, garlic, sesame seeds, baking powder, parsley stalks and ½ tbsp water into a food processor. Blitz until everything is combined but not mushy – you want the falafel to have some texture, rather than being like hummus. Season to taste, then roll into 18 even-sized balls. Flatten each ball into a disc shape and put them on the baking sheet (the more surface area the crisper they will become). Brush them with ½ tbsp oil. Bake for 20 mins, turning halfway, until golden and crisp.
Meanwhile, clean the food processor. Briefly pulse the cauliflower until you have a couscous consistency. Mix the cauliflower with the remaining ground spices, olive oil and seasoning. Tip onto a baking tray and roast for 10-12 mins, stirring occasionally, until slightly toasted. Once cool, mix through the chopped parsley, mint and a squeeze of lemon juice. Season to taste.
Put the frozen peas in a microwavable bowl, cover and cook on high for 2-3 mins. Drain off all the water, then roughly mash. Add the avocado and mash again to combine. Crumble in the feta, mix, then add the lemon zest and another squeeze of lemon juice, and seasoning to taste.
Toss the rocket leaves in a final squeeze of lemon juice, then serve with the falafel and cauliflower tabbouleh, rocket and the pea and avocado smash.