Pre-heat the oven to 200C/180C Fan/Gas 6.
Line a baking tray with kitchen foil and place the beetroots in the middle. Season with salt and pepper and drizzle with oil. Wrap the foil up around the beetroots, seal and bake for 1 hour.
Place a small frying pan over a low heat and toast the nuts and cumin seeds for 2 minutes. Remove from the heat and allow to cool in the pan.
Peel and cut the beetroot into 2cm/1in cubes and place in a large, glass bowl. Stir in the apple, nuts, seeds and herbs.
To make the dressing, mix the ingredients together in a bowl. Just before serving, dress the salad and mix well.