Trim and wash spinach and break it with your hands. Dice bacon and brown in a spoonful of oil. Peel the apples and cut into segments.
In a bowl, mix the remaining oil with vinegar, salt and pepper. In a salad bowl, mix spinach, bacon and apples. Pour on the dressing, mix and sprinkle with slivers of Grana Padano and garnish with salt and pepper.