Prepare the ingredients and get your equipment ready. Preheat oven to 200°C/400°F/gas mark 6.
Put the new potatoes in a saucepan and cover with cold water. Add vinegar and 1 teaspoon of sea salt to the saucepan. Bring to the boil and then cook for about 15-20 minutes (depending on the size of the new potatoes). Drain the new potatoes in a colander and leave for about 5 minutes until slightly cooled and no longer steaming.
Lay the new potatoes out on a baking tray with the shallots, coat with olive oil and season with the remaining salt and pepper. Bake for 20-30 minutes. At the halfway point, add the rosemary and give everything a good toss. In the last 2 minutes of roasting, add the garlic. After 2 minutes, remove from the oven, serve and enjoy!