Preheat your oven to 400°F (200°C). Pierce each potato several times with a fork to allow steam to escape, then wrap each potato in foil. Place them directly on the oven rack and bake for about 60-70 minutes, until soft and tender when pierced with a knife.
Once the potatoes are cooked, carefully remove them from the oven and unwrap. Let them cool slightly for easier handling. In the meantime, prepare the toppings by arranging them in separate bowls for a colourful presentation.
Slice each potato lengthwise down the middle, being cautious not to cut all the way through. Use a fork to gently mash the insides, loosening the potato flesh without tearing the skin.
Add about 1 tablespoon of butter and 1/4 cup of shredded cheese to each potato, mashing and mixing the filling with a fork directly inside the potato. The cheese will melt from the residual heat, creating a creamy, flavourful base.
Season the mashed potato filling with a sprinkle of salt and black pepper, adjusting to taste. Continue to mash and mix until the butter and cheese are fully incorporated, giving the potatoes a smooth, rich texture.
Fill each potato generously with your choice of toppings, starting with hearty options like diced sausage, peas, and carrots, followed by fresh ingredients like bell peppers, corn, and olives. The variety of colours and flavors is part of what makes kumpir special.
Drizzle a small amount of mayonnaise and ketchup over the toppings for added flavour. You can also add extra shredded cheese on top if you like your kumpir extra cheesy.
Serve the kumpir hot, either in the foil for a rustic presentation or on a plate, garnished with a bit more pickled cabbage if desired. Kumpir is enjoyed as a meal on its own, with each bite offering a delicious mix of creamy potato, melty cheese, and flavourful toppings.