Russian salad recipe

Ingredients

• 200 gm (about 3) waxy potatoes, such as Nicola, cut into 1.5cm dice
• 150 gm celeriac, peeled and cut into 1.5cm dice
• 2 carrots, cut into 1cm dice
• 120 gm (¾ cup) frozen peas, defrosted
• 2 tbsp mayonnaise
• 2 tbsp crème fraîche
• 2 tbsp jarred or freshly grated horseradish (see note)
• 2 tbsp finely chopped chives
• Juice of ½ lemon
• Cooked king prawns or lobster, to serve