Trim the aubergines and courgettes and chop them into bite-sized chunks. Peel and finely slice the onions. Peel and grate the garlic. Separate the chard leaves and stalks. Finely slice the stalks and roughly chop the leaves.
Pour 1 tbsp oil into a large pan and bring to a high heat. Slide in the aubergines with a little salt and pepper. Fry for 5-6 mins, stirring occasionally, till coloured on the outside and tender in the middle. Use a slotted spoon to transfer to a plate.
Pour another 1 tbsp oil into the empty pan. Reduce the heat to medium and slide in the onions, courgettes, chard stalks, garlic, 1 tsp ground cumin and a pinch or 2 of harissa (harissa is hot, so use less for a milder flavour). Cook for 5 mins, stirring now and then, till starting to soften.
Tip in the chopped tomatoes, drop in the cinnamon stick and return the cooked aubergines to the pan. Bring to the boil, then tip in the bulgar wheat and pour in 800ml boiling water. Stir in the chard leaves. Reduce to a simmer, cover the pan with a lid and cook for 10 mins.
Remove the pan from the heat and allow to steam and finish cooking in the pan for a further 5 mins.
Grate in the lemon zest and squeeze in half of the juice. Have a taste and add more salt and pepper if you think it needs it. Spoon into bowls and serve with the remaining lemon, sliced into wedges.