Start by filling a large pot with water and adding a generous pinch of salt. Bring the water to a rolling boil, then carefully add your small or medium potatoes. Boil the potatoes for 20 to 30 minutes, or until they are fork-tender.

After draining, let the potatoes sit in the colander for about 5 minutes to allow them to dry out completely.

Place the dried potatoes on a lined baking tray and gently smash each potato until it's flattened but not completely broken apart, keeping the rustic shape.

Let the smashed potatoes sit for another 5 minutes to ensure that extra moisture escapes.

Melt the unsalted butter and combine it with olive oil. Drizzle this mixture generously over the smashed potatoes, ensuring they are well-coated. Finish by sprinkling salt and black pepper.

Carefully place the baking tray in your preheated oven and let the potatoes bake for 45 to 55 minutes until golden brown.

Allow the potatoes to cool slightly before serving. Optionally, sprinkle finely chopped parsley over the potatoes.