Beef burger with sweet potato chilli chips

• large, roundish sweet potatoes↗4

  cut into chunky chips

• olive oil↗1 tsp tsp
• chilli flakes↗1 tsp tsp

  plus a pinch

• pack extra-lean beef mince↗400g g
• onion↗1

  grated

• grated parmesan1 tbsp tbsp
• tomato ketchup↗1 tbsp tbsp
• small wholemeal buns↗4

  halved

• Little Gem lettuce↗1

  leaved separated

• beef tomato1

  sliced

• red onion↗1

  sliced (optional)

• pickles or gherkins↗4

  halved

Step-by-step instructions

1. 1

   Heat oven to 220C/200C fan/gas 7. Toss the chips with the oil, 1 tsp chilli flakes and some seasoning. Arrange in a single layer on a large baking tray and cook for about 30 mins, turning halfway through.

2. 2

   Put the mince, remaining chilli flakes, onion, Parmesan, tomato ketchup and lots of black pepper in a large bowl and mix to combine. Shape into 4 burgers. Ten mins before the chips are ready, put the burgers on a baking tray and bake for 10 mins until cooked through.

3. 3

   Top one half of the buns with the lettuce, tomato and onion. Add the burgers, then top with the roll tops. Serve with chips and pickles on the side.