Begin by heating a frying pan with olive oil over medium heat and adding the bacon to fry until crispy. Allow it to cook for a few minutes until it achieves a golden hue and develops a crispy texture. Transfer the bacon to a plate lined with paper towels to absorb any excess fat. In the same frying pan with the remaining oil, add the diced potatoes. Cook them until they soften and acquire a golden-brown color, stirring occasionally to prevent sticking. Meanwhile, in a bowl, prepare the omelette mixture. Using a fork, beat the eggs with milk and season with salt and pepper to taste. Once the mixture is well-combined, transfer it to the warm pan. Spread the cooked potatoes, crispy bacon, and grated cheese evenly over the omelette. Place the pan in the oven and bake for 10 minutes at 180°C. Once the omelette is beautifully golden brown, remove it from the oven, sprinkle fresh parsley on top, and savor it while still warm.