Mushroom-and-Beef Burgers - Cookbook Interactive

Ingredients

• 150g mushrooms
• 1 (medium) onion
• 1 tbsp clarified butter
• salt
• freshly ground white pepper
• 2 slices white bread
• 350g minced beef
• 1 (small) egg
• 1 tsp dried mixed herbs
• 4 sesame seed buns
• 2 tbsp mayonnaise
• 2 tsp French mustard
• 1 cucumber
• 8 lettuce leaves