Sloppy joes

2 tbsp olive oil

• 400g beef mince

• 1 onion, finely chopped

• 1 green pepper, finely chopped

• 1 tsp garlic granules

• 1 tsp smoked paprika

• 1 tsp light brown soft sugar

• 1 tbsp malt vinegar

• 4 tbsp ketchup

• 1 tbsp Dijon mustard or 1⁄2 tsp mustard powder

• 300ml beef stock

• 4 burger buns, split

• chilli sauce, to serve (optional)