Green Meadows Beef - Angus Beef Cheeseburger

Ingredients

• 3 tablespoons olive oil
• 1 tablespoon butter
• 1 large brown onion, cut into rounds
• 500gms Green Meadows Beef Mince
• 1 egg
• ½ small red onion, finely chopped
• 1 clove garlic, minced
• 1 tablespoon thyme, leaves removedfrom stalks
• 2 teaspoons wholegrain mustard
• ¾ teaspoon flakey sea salt
• Buns, sliced in two
• 6 thick slices tasty cheese
• Gherkins, sliced lengthways
• Mayonnaise
• Tomato sauce