Heat 2 tablespoons of olive oil in a saucepan and add the orzo. Sautee for a couple of minutes. Add plenty of boiling water and cook the orzo according to the pack instructions, until al dente. In the meantime, in large frying pan, heat the rest of the olive oil and add the onion and mushrooms. Cook for a couple of minutes and then add the spinach. Cover the pan and let it cook for 2 minutes. Uncover and add the white wine. When it has evaporated, add the pesto and cream. Add salt and pepper and mix in the cooked orzo. Cook for another 2-3 minutes and serve.