Prepare the potatoes: Peel and cut the potatoes into thin strips. Rinse them under cold water and pat them dry with paper towels to remove excess moisture.
Season the potatoes: In a large mixing bowl, toss the potato strips with salt, pepper, and cornstarch. Make sure they are evenly coated, which helps achieve that crispiness.
Fry the potatoes: Heat vegetable oil in a deep pan over medium-high heat. Fry the potato strips in batches for about 3-4 minutes until golden brown and crispy. Remove them from the oil and drain them on paper towels.
Make the cheese sauce: In a separate pan, sauté the onion, garlic, and red bell pepper in a little oil until softened. Add the grated cheese (reserve 50g) and stir until it melts into a creamy sauce. Season with salt and pepper to taste.
Serve: Arrange the crispy potato strips on a plate, drizzle the cheese sauce on top, and garnish with chopped parsley. Serve hot and enjoy!