smoked mackerel, beetroot and horseradish baked potatoes

2 smoked mackerel fillets
1 tbsp Greek yoghurt
1 tbsp horseradish sauce
2 spring onions, finely chopped
Handful of watercress
Squeeze of lemon juice
Decent pinch of cayenne pepper
Sea salt and freshly ground black pepper
2 cooked beetroot, cut into bite-size pieces
2 baked potatoes

Flake the mackerel into a mixing bowl and gently stir through the yoghurt, horseradish sauce, spring onions, watercress, lemon juice and cayenne pepper. Season with salt and pepper. Add the beetroot just before you are ready to eat. Divide the mixture between the potatoes.