In a saucepan, soften the leek in the oil over medium heat for about 2 minutes. Add the celery and apple. Deglaze with the wine and reduce for 1 minute. Add the broth and rice. Cook over medium heat for about 20 minutes, uncovered. Five minutes before the end of cooking, add the spinach. Purée in a blender. Return to the saucepan and add the cream. Stir and reheat without boiling. Season with salt and pepper. Before serving, garnish with walnuts and cheese.