Mix all ingredients to make the pork marinade. Add the pork to a sandwich bag, add the marinade and leave for at least half an hour (ideally overnight).
Meanwhile, make the potato salad by mixing all the ingredients and stirring through the cooled, cooked potatoes.
Heat a griddle pan over a high heat and cook the medallions for 2 minutes each side. Serve with the potato salad.
300g salad potatoes (such as Charlotte), pre-boiled, cooled and roughly chopped
1 pork tenderloin, sliced into 1.5cm medallions
For the pork marinade
2tbsp olive oil
2tbsp cider vinegar
1 garlic clove, grated
¼tsp fine salt
2tsp caraway seeds, crushed with a pestle and mortar
1tsp grainy mustard
For the potato salad
1 small banana shallot, finely chopped
½tbsp cider vinegar
1tsp Dijon mustard
3 stalks dill, fronds removed
30g gherkins, finely chopped
50g radishes, thinly sliced (a mandolin would be ideal)