Melted sandwich with Old Amsterdam Matured, caramelized onion, walnuts and thyme - Old Amsterdam

Ingredients

• 1 piece of Old Amsterdam Matured to shave, or 4 pre-packed slices
• 2 slices of white or brown sourdough bread
• 2 red onions
• 2 tbsp olive oil
• 2 tbsp balsamic vinegar
• 2 sprigs of finely chopped fresh thyme
• 1 tsp honey
• 1 handful coarsely chopped walnuts
• Salt and freshly ground black pepper