Heat a deep pan half-filled with vegetable oil until a breadcrumb sizzles.
Whisk gram flour and 150ml water into a pouring cream consistency.
Mix in the chopped chilli and set the batter aside in a cool place.
Fry sliced onion in 2 tablespoons of oil until softened and drain on kitchen paper.
Mix the 200g sprouts, 100g green beans, and fried onion in a bowl.
Dip tablespoon-sized amounts of the mixture into the batter to coat.
Deep fry the coated mixture until golden-brown and drain on kitchen paper.
Combine 250g yoghurt, mint, and lime juice in a bowl and season.
Serve the hot bhajis with the yoghurt dressing for dipping.