Niman Ranch burgers Recipe | Food Network UK

Ingredients

• 900g minced Niman Ranch beef or other grass-fed premium beef (80% lean/20% fat)
• 1 tbsp good Dijon mustard
• 3 tbsp good olive oil, plus extra for brushing the grill
• 1 tsp salt
• 1 tsp freshly ground black pepper
• 3 sandwich-size muffins
• Good mayonnaise
• Caramelized onions, recipe follows
• For the caramelized onions
• 2 tbsp good olive oil
• 30g unsalted butter
• 900g yellow onions, peeled and sliced in half-rounds
• 1/2 tsp fresh thyme leaves
• 2 tbsp sherry wine vinegar
• 1 tsp coarse salt
• 1/2 tsp freshly ground black pepper