Scatter the cardamom pods into a pestle and mortar and crush (see our tip below if you don't have a pestle and mortar). Discard the papery husks. Peel and finely chop or grate the ginger and garlic cloves and add to the cardamom. Spoon in the garam masala, turmeric, and cumin along with a good pinch of salt and pepper. Grate in the lemon zest and pour in 1 tbsp oil. Stir till everything is well mixed into a paste.

Peel the sweet potato and cut roughly into 1cm dice. Chop the tomatoes into small pieces. Trim the root off the broccoli and slice the florets into small pieces. Peel and finely slice the onion. Prick the chilli a few times with a sharp point of a knife.

Pour 1 tbsp oil into a large pan and bring to a high heat. Slide in the sliced onion and cook for 3-4 mins, stirring frequently, till crispy and deep gold in colour. Scoop the onions into a bowl and set aside. Reduce the temperature of the pan to medium.

Add the sweet potato and chilli to the empty pan and scrape in the spice mix. Fry for 5 mins, stirring occasionally. Slide in the sliced broccoli and the chopped tomatoes and continue to cook for a further 5 mins.

Pour 1 ltr boiling water into a jug and crumble in the stock cube. Stir will to dissolve.

Scatter the rice into the pan and add the cinnamon stick. Pour in the stock and stir well. Pop a lid on the pan and bring to the boil. Reduce to a simmer and cook for 8 mins, then remove from the heat and allow to steam for a further 10 mins.

Roughly chop the coriander. When the rice is cooked, stir in the coriander, cooked onions and half of the lemon juice. Have a taste of the rice, and add more salt if needed.

Spoon the biriyani onto plates and serve with wedges of the remaining lemon.