Cook the potatoes in a large saucepan of salted boiling water for about 10 minutes, until just
tender. Drain in a colander, then rinse in cold water. Drain again. Leave until cool enough to
handle, then peel off the skins. Melt the butter in a large frying pan and gently fry the onion and
garlic for about 3 minutes until softened and beginning to colour. Remove from the heat.
Coarsely grate the potatoes into a large bowl, then stir in the onion and garlic mixture.
Sprinkle over the parsley and stir well to mix. Season to taste with salt and pepper. Heat the oil
in the frying pan and cover the base of the pan with half the potato mixture. Lay the slices of
Parma ham on top. Sprinkle with the chopped sun-dried tomatoes, then scatter the grated Emmenthal
over the top.
Finally, top with the remaining potato mixture. Cook over a low heat, pressing down with a
palette knife from time to time, for 10-15 minutes, or until the bottom is golden brown. Carefully
invert the rosti onto a large plate, then carefully slide back into the pan and cook the other side
until golden. Serve cut into wedges, with a mixed green salad.