Place the pine nuts (or hazelnuts) on non-stick foil under the grill and cook until brown - this will only take a few minutes, and they do need watching carefully as they can easily burn if left too long. Remove from under the grill and allow to cool. Prepare the beetroot by trimming and washing the leaves and scrubbing the bulbs.
Bring a saucepan of water to the boil, place the beetroot in the water then return to the boil, cover and reduce the heat. Simmer the beetroot until tender. (This will probably take around 30 minutes. Pierce with a knife to test that it is tender right through to the middle.).
Once tender, remove from the pan, drain and leave until to cool enough to handle then peel off the skins (I like to wear kitchen gloves for this so that my hands aren’t stained deep purple all day) and cut into wedges.
Meanwhile, boil the green beans for 2 – 4 minutes (they should be tender but still crisp). Place a sieve or colander over a bowl large enough to accommodate the water from the saucepan. Tip the beans into the sieve and reserve the hot water.
Then turn the green beans out of the sieve into a bowl of ice-cold water (this will arrest the cooking process and the beans will retain their vibrant green colour).
Return the hot water in to the saucepan and bring back to the boil. Add the beetroot leaves/baby spinach and cook briefly. Once tender, drain in the same manner as the green beans, and again - plunge into a bowl of cold water, then drain again (or, if you have a salad spinner, spin them until dry enough to serve).
Make the dressing by placing the vinegar, oil, garlic, capers, and salt and pepper in a seal-tight jar and shaking to combine.
The salad can either be served warm or cold. If you decide to serve it cold, keep all the ingredients separate whilst cooling or the beetroot colour runs into the green beans and cheese.
To serve: place the leaves on 4 salad servers, carefully place beetroot wedges on top then arrange the green beans among and on top of the beetroot. Lastly, crumble the feta cheese over the salad and drizzle with the salad dressing.