Heat the oil in a pan, sauté the onion and garlic for approx. 3 mins., mix in the walnuts and beetroot, allow to cool a little. Stir in the egg, season with salt. Preheat the oven to 60°C, warm the platter and plates.
Divide the filling into four portions, place in the middle of the strips of pasta dough at equal intervals. Brush the second roll of pasta dough with a little egg, place over the filling, press the edges down firmly, pressing out any trapped air. Using a pastry wheel, cut the ravioli into pieces of equal size.
Bring the beetroot juice and salted water to the boil in a pan, reduce the heat. Cook the ravioli in batches in just-boiling beetroot water for approx. 5 mins. Remove with a slotted spoon, drain and keep warm.
Serve the spinach and ravioli on warmed plates, sprinkle the remaining ingredients over the top.