Peel and cut into 4cm chunks the sweet potatoes. Finely chop the spring onions. Chop the fresh coriander.
- 1 Heat the oven to 190°C/170°C fan/gas 5.
- 2 Arrange the sweet potatoes in a single layer in a large roasting tin.
- 3 Drizzle with olive oil, season with salt and roast for 35-45 minutes, until golden on the outside and just tender when pierced with the tip of a sharp knife.
- 4 Remove from the oven and set aside until cold.
- 5 Tip the sweet potatoes onto a large board and very roughly chop them.
- 6 Put them in a bowl and stir in the breadcrumbs, cayenne pepper, spring onions and coriander.
- 7 Shape the mixture into 4 burgers and place them on a plate.
- 8 Cover and chill for 1 hour.
- 9 Pour sunflower oil into a large non-stick frying pan to a depth of 2cm, then heat.
- 10 Dust the burgers with a little plain flour – they will be quite soft, so handle gently – and carefully lay them in the pan.
- 11 Cook for 4-5 minutes each side until crisp and golden.
- 12 Remove with a fish slice and drain on kitchen paper.
- 13 Halve and toast the buns.
- 14 Arrange lettuce and tomatoes on the bottom half of each bun and place a burger on top.
- 15 Spoon over a little Guava Ketchup and top with the other bun halves.
Put off trying this by the very high carb content. With sweet potato, bread and breadcrumbs as the main ingredients, it doesn't seem suitable for a balanced vegetarian diet. Not enough protein content.