Place the diced potatoes in a large pot, cover with cold water, add a good pinch of salt and bring to a boil. Simmer until potatoes are just barely tender when pierced with a knife; do not overcook. Drain well.

Meanwhile, heat a 10-inch (25 cm) cast iron skillet over low-medium heat and add 1 1/2 tablespoons of the Garlic-Infused Oil and heat until shimmering. Add the leeks, season with some salt and pepper and sauté, stirring often, until softened, but not browned, about 5 minutes.

Scrape sautéed leeks out into a small bowl and set aside. Add remaining oil and 1 tablespoon of butter to the pan, still over low-medium heat, and heat until butter melts. Add the drained potatoes, season with salt and pepper and toss them well to coat in the hot fat. Turn heat up to medium.

Allow (or coax) the potatoes to be in a single layer and leave undisturbed, for several minutes, or until the bottoms are nice and crispy and golden brown. Flip the potatoes over with a broad spatula, getting as many new surfaces facing down as possible, in contact with the hot pan. Add the remaining butter at this point if the mixture appears dry. Again, leave the potatoes undisturbed and cook until crispy.

Scrape the leeks into the potatoes and fold together well. Taste and adjust seasoning and add the smoked paprika, if using. Serve immediately. Preferably with eggs, over easy, with runny yolks to mix in with eat bite of potato.