Beetroot tartar with zesty apple

Ingredients

• 200 g herbed serac cheese (or ricotta) 
• 100 g fresh Philadelphia-type cheese
• 1 tsp chopped chives
• 500 g cooked beetroot, finely diced or cut into very thin strips
• 1 red apple, peeled and cut into very thin strips
• 10 small gherkins, finely chopped
• 1 small shallot, finely chopped
• 3 tablespoons coarse-grain mustard
• 2 tablespoons soy sauce
• ½ tsp. chilli flakes
• 5 tbsp. lime juice
• salt and pepper
• 4 tbsp. sour cream