For the baked potato, wrap the potatoes in tin foil. Bake on a medium rack in a heated oven at 220° C (gas 3-4, convection oven 200° C) for 1 hour.
Chop onions into cubes, chop garlic into thin slices. Roughly chop thyme and parsley leaves.
Finely grate the zest of an untreated lemon. Heat oil, fry onions and garlic in it, season with salt and pepper. Add capers, thyme, parsley and lemon peel.
Remove the potatoes from the oven, score them crosswise, press them open and drizzle the baked potato with the herb oil.