The Ultimate Irish Steak Sandwich - Irish Beef

Ingredients

• 2 Irish Sirloin steaks, about 300g each
• Splash of vegetable oil
• 2 onions, thinly sliced
• 4 large field mushrooms, thickly sliced
• 1 tbls of mayonnaise
• 1 tbls of marmite
• 2 medium ciabattas or baguettes
• English mustard, for spreading
• Salt and freshly ground black pepper
• 50g butter
• 50g flour
• 1 tbls English mustard
• 150g medium cheddar cheese grated
• 150ml beer
• Ingredients
• Method