Fill an empty jar with all the ingredients for the dressing and cover with the lid. Shake well, taste for salt and pepper and save the dressing until used. Heat a non-stick pan and add a teaspoon of olive oil. Fry the raw ham on both sides until crunchy and drain on kitchen paper. Do not fry too many slices at the same time, but two by two, keeping them whole. Quarter the pears and remove the core. Cut into strips. Combine the cheese, onion rings and ham with the spinach leaves. Transfer the salad to a plate, arrange the pears and top with dressing. Serve with pumpkin buns and eat immediately.