Half-fill a large pan with cold water, add the bulgur wheat and leave to soak for 20 minutes, then drain and rinse well. Tip back into the pan and top up with cold salted water.
Bring to the boil over a high heat, pop the lid on, then reduce to a low heat for around 20 minutes, or until cooked through but still with a bit of bite, stirring occasionally.
Meanwhile, peel the onion and 1 clove of garlic and trim the celery and carrot, then roughly chop and place into a processor. Blitz until finely chopped.
Heat 1 tablespoon of oil in a large ovenproof frying pan over a medium heat, add the blitzed veg and fry for 12 minutes, or until softened, stirring occasionally.
Once cooked, drain the bulgur wheat and leave to cool.
Pick the parsley leaves and put to one side, then roughly chop the stalks. Place the stalks and most of the leaves into the processor. Drain and add the chickpeas, then crack in the egg. Add the breadcrumbs and half the cooled bulgur, then blitz to a rough paste.
Tip into a large bowl with the cooked vegetables and the remaining bulgur.
Finely grate in the lemon zest and Parmesan, then add it to the bowl. Season with a pinch of black pepper and mix well with your hands until smooth.
Divide and roll the mixture into golf-ball-sized balls, placing them on a tray as you go – you should end up with 24 in total. Cover the tray with clingfilm and place in the fridge for 30 minutes to firm up.
Preheat the oven to 200ºC/400ºF/gas 6.
Peel and finely chop the remaining garlic. Return the large ovenproof frying pan to a medium heat, drizzle in 1 tablespoon of oil, then add the garlic and cook for 2 minutes, or until golden.
Tip the tomatoes, breaking them up with a wooden spoon, then pour in ½
a tin’s worth of water. Reduce the heat to low and simmer for around 5 minutes, or until thickened. Squeeze in half the lemon juice.
Once the veggie balls are firm, remove from the fridge.
Heat 2 tablespoons of oil in a large non-stick frying pan over a medium heat, add the balls and cook for around 8 minutes, or until browned all over, turning occasionally, then transfer to the tomato sauce.
Tear the red peppers into strips with your fingers, then arrange in the sauce. Season the sauce to taste and dot over the ricotta.
Place the pan in the oven for around 20 minutes, or until golden and bubbling. Serve with a scattering of parsley leaves and lemon wedges for squeezing over.