Before starting, make sure that all of your prep work is done (veggies chopped and aubergine microwaved; black beans roughly crushed).
Make the sauce: first mix the cornstarch with a splash of water to form a paste, then add all the rest of the sauce ingredients and set aside.
Spray a wok or frying pan with non-stick spray, and start frying your veggies. Start with the onion and carrot, tossing constantly and adding a splash of water if needed to prevent sticking. Toss for a minute or two.
Add the aubergine and broccoli, then continue to toss for a few minutes until the aubergine is completely cooked and the broccoli is bright green. You want the broccoli to maintain a crunch. Keep adding splashes of water if needed.
Add the black beans, and then the mangetout / sugar-snap peas (if using).
Add the sauce and toss around for 60-90 seconds, making sure that the sauce coats all the vegetables and cooks the cornflour without sticking and burning on to the pan. Continuous movement is the key here. The sauce will thicken.
Add the cashews (if using), turn off the heat, squeeze over the lemon / lime juice, and garnish with toasted sesame seeds.
Serve immediately