Prepare the ingredients: Wash the baby potatoes in water without removing the skin, then cut them in half. Grate the cheddar cheese. Chop the Jalapenos into small pieces. Slice the sun-dried tomatoes and black olives.
Boil the potatoes: Prepare a large pot and add the potatoes. Add enough water so that all the potatoes are immersed. Parboil the potatoes for fifteen minutes. Once parboiled, remove the potatoes from the pot and allow them to cool completely.
Bake the smashed potatoes: Place the parboiled potatoes on the baking tray with the skin side up. Press down with your palm against the potatoes to gently smash them. Then, add the toppings, such as cheddar cheese, Jalapeno, black olives, and sundried tomatoes. Sprinkle a pinch of celery salt.
Bake the potatoes in three parts: The first fifteen minutes at 220ºC with the fan on, then the next fifteen minutes with the fan off. In the last ten minutes, reduce the temperature to 140ºC. For the oven without a fan, keep the temperature to 200ºC for the entire forty minutes of baking time. Check the potatoes every fifteen minutes and control the temperature accordingly. Serve the smashed potatoes while they are still hot.