Colorful Tomato Salad

Halve and peel the avocado. Remove the seed and mash the fruit with a fork. Finely grate half of the cheese, and mix with the creme fraiche and avocado. Season to taste with the wasabi and sea salt, then mix into the vegetables. Use a ring form to stack the salad onto plates. Slice the remaining cheese, and cut into strips. Top the salad with the cheese and watercress. Garnish with the balsamic crema.