Pre-heat the oven 200ºc fan. Spray 2 baking trays with low-calorie cooking spray and use to grease the trays.
Mix the cornflour with the garlic granules and season with salt and pepper.
Coat the vegetables in cornflour, then dip in the egg white and thoroughly coat in breadcrumbs. Place on the baking trays and spray with a little low-calorie cooking spray.
Bake for 15- 20 minutes until golden and the vegetables are just tender. Move the position of the trays once or twice during cooking to ensure even cooking.
Mix the mayonnaise, sriracha sauce, lemon juice and coriander together in a small bowl and season to taste with salt and pepper.
Serve the vegetable tempura immediately with the dip.