Whip up 4 tablespoons mint yoghurt sauce and 2 tablespoons tamarind chutney, then set aside. You can also buy these!
In a large bowl, combine 200 g onion (sliced), ¼ teaspoon turmeric powder, ½ teaspoon red chilli powder, ½ teaspoon amchoor powder, ½ teaspoon salt, 1 teaspoon ginger garlic paste, 1 small handful fresh coriander (chopped), and ½ teaspoon ajwain seeds (crushed between your palms). Next, add 100 g gram flour and massage the mixture together with your hands. Slowly drizzle in 100 ml water while continuing to massage.
In a large, deep-sided frying pan over medium heat, add 1 litre neutral oil. Always exercise caution! Once the oil is hot (test it with a wooden skewer or spoon — if the oil bubbles around the wood, it's ready), carefully spoon in the bhaji mixture, making patties about the size of your buns. Make four total. Don't overcrowd the pan, so cook in two batches if necessary.
Cook until golden brown on one side, then gently turn and cook on the other side until golden brown. This may take around 10 minutes.
Drain the onion bhajis on kitchen paper and turn off the stove.
Cut 2 brioche buns** in half and spoon tamarind chutney* onto the bottom side. Layer it up with 1 handful mixed salad leaves, then a bhaji. Spoon yoghurt mint sauce on top, then another bhaji. Complete with more yoghurt mint sauce, then the top bun. Repeat with the other burger**
Notes
* You can switch tamarind chutney to mango chutney if you prefer. This is a sweeter option. ** If you prefer, add only one bhaji per burger and make four burgers instead of two. I love the mammoth crunch effect with two though!