Cheeseburgers with Secret Sauce

Name: Cheeseburgers with Secret Sauce
Prep time: 20 min
Cook time: 15 min
Total time: 35 min
Cuisine: American
Ingredients: 600g Quality Mark beef mince; 1/2 onion; 1 garlic clove; 1 egg; 1 toast slice wholemeal bread; 2 tbsp milk; a small handful of chives; a small handful of parsley; 1/2 cup grated tasty Cheddar cheese; 2 tbsp tomato paste; 1 tbsp olive oil; 1/2 tsp Worcestershire sauce; 8 slices cheddar cheese; 3/4 cup mayonnaise; 1 shallot; 3 gherkins; 1 tbsp tomato paste; 1 1/2 tbsp Dijon mustard; 4-5 white bread rolls; 4-5 leaves lettuce; 1 red onion