Make the horseradish cream dressing by mixing everything in a small bowl. Season to taste with salt and freshly ground black pepper. Set aside.
Toss the salad leaves in a little extra virgin olive oil and divide between four dishes. Scatter over the beetroot, radishes, celery and spring onions. Finally, top each with a trout fillet and a generous dollop of dressing. Serve immediately.
For further information visit www.lovebeetroot.co.uk