Curried red potato salad with broccoli

Ingredients

• about 500 gram red potatoes
• 1/2 broccoli
• 1 red onion
• 2 apples (e.g. Golden Delicious)
• 1 lemon
• 2 tablespoons curry powder
• large dash of sunflower or other neutral oil
• 3 tablespoons crème fraîche or sour cream
• pepper and salt to taste
• handful of croutons