Feta Stuffed Lamb Burgers with Harissa Aubergine Jam

Name: Feta Stuffed Lamb Burgers with Harissa Aubergine Jam
Ingredients: 1 aubergine; 2 large red chillies; 250g cherry tomatoes; 80g dark brown sugar; 75ml cider vinegar; 1 lemon, juiced; 1 tbsp harissa paste; Salt, to taste; 250g lamb mince; 2 tsp ground cumin; 1/2 tsp smoked paprika; 3 garlic cloves, grated; Salt and pepper, to taste; 25g feta; Handful rocket leaves; handful Fresh coriander; 2 tbsp olive oil; Salt and pepper; 2 brioche buns; 1/2 red onion, thinly sliced