Heat 2 tablespoons of olive oil in a large saucepan over medium–high heat until shimmering. Add 1 thinly sliced small red onion, season lightly with salt, and cook for about 3 minutes, stirring occasionally, until beginning to soften.

Increase the heat until the mixture begins to boil. Reduce the heat to maintain a gentle, steady simmer with small bubbles breaking the surface. Cook for about 20 minutes, stirring occasionally to prevent sticking, until the potatoes are soft enough to mash.

Reduce the heat to medium–low. Using a potato masher, sturdy fork, or the back of a wooden spoon, mash the vegetables in the pan until you reach your preferred consistency—smooth or slightly chunky. Cook for another 2 minutes. (Bear in mind that the cheese will thicken the soup further.)

Stir in most of the 90 g of grated Grana Padano, reserving a little for garnish. Taste and adjust the seasoning with salt and pepper if needed. Serve in bowls topped with the remaining cheese, a few grinds of black pepper, and a drizzle of olive oil.

Note: the amount of cheese probably should be about twice the amount but this is a healthier version of the dish. If served for people, you may want to consider doubling the amount of cheese.