Onion Marmalade, Gruyere and Sage Stuffed Flank | KARAN BEEF | KARAN BEEF

Ingredients

• 1 kg flank steak
• 120 g gruyere cheese, grated
• 6 sage leaves, chopped
• Onion marmalade
• 1 Tbsp butter
• 2 large red onions, thinly sliced
• 4 Tbsp brown sugar
• 2 Tbsp red wine vinegar
• 1/4 cup balsamic vinegar
• 1 tsp mustard seeds
• Salt and freshly ground black pepper