Jacket potatoes with curry sauce

Ingredients

• 3 potatoes
• 80 g white mushrooms
• 1 carrot
• ½ onion
• ½ celery stalk
• 3 tablespoons sour cream
• Pinch of salt
• Dash of ground black pepper
• Grated hard cheese
• 200 g sour cream
• 100 g Greek yogurt
• 1 tablespoon lemon juice
• 1 tablespoon curry powder
• 2 tablespoons fresh cucumber juice
• 2 dashes ground black pepper
• 2 pinches of salt
• Pinch of Cayenne pepper