Preheat your oven to 200°C (400°F).2. Wash the large potatoes thoroughly. Prick each potato several times with a fork.3. Place the pricked potatoes directly on the oven rack. Bake for 60 to 90 minutes, or until they are very tender when squeezed.4. While the potatoes are baking, prepare the other ingredients. Grate 150g of cheese.5. Finely chop one large onion and one large red pepper.6. In a large bowl, combine the grated cheese, chopped onion, and chopped red pepper.7. Add a good sprinkling of salt and pepper to the bowl. Add a pinch of red chilli flakes if you like. Mix these ingredients together.8. Once the potatoes are baked, carefully remove them from the oven.9. Working quickly, cut each potato lengthwise down the middle, but do not cut all the way through the skin at the bottom.10. Scoop out the soft potato flesh into the cut potato skin, leaving a border of potato flesh against the skin.11. Add 2 tablespoons of butter and some of the grated cheese to the scooped potato flesh.12. Mash the butter and cheese into the potato flesh directly inside the potato skin until creamy.13. Now, add your prepared mixture of chopped onion, red pepper, salt, pepper, and chilli flakes into the mashed potato.14. Stir gently to combine these fillings within the potato.15. Serve immediately with any additional optional toppings you desire.