Heat a large non-stick skillet over high heat. Add the speck, or bacon, to the hot pan. The pan needs to be very hot so that the speck is crispy. When cooked through and crispy, remove the speck and let drain on paper towels.
Grate the potatoes on a mandoline adjusted to the julienne setting. Do not grate them ahead of time, or they will turn color. Wring the potatoes out with your hands to get rid of excess moisture. In a medium bowl, combine the shredded potatoes, thyme, pepper, and speck mixing with your hands. Add flour to the mixture to bind it. Form the potato mixture into 4 patties.
In the same skillet, add enough oil for frying, plus the 2 tablespoons butter. Heat over high heat until oil is very hot. Add the potato cakes, making sure there is at least 1/2-inch between them. Cook for several minutes on each side, until golden brown and crispy on all edges, and cooked through in the middle. The amount of cooking time will vary based on the thickness of the potato cakes.
Remove potato cakes from oil and let drain on paper towels. Season with salt while hot.
In a medium bowl, whisk together the creme fraiche, honey mustard, lemon juice, and horseradish. Add the cilantro and chives, and stir to combine. Just before serving, add the salad greens to the bowl, and toss.
To plate, put 1 potato cake on each of 4 plates. Top each potato cake with 3 slices of smoked salmon. Add a pile of greens with dressing on top of the salmon. Sprinkle salads with pepper, and garnish with lime wedges on the side.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.