Buttery fingerling potatoes smashed and roasted until shatteringly crisp outside and fluffy within, then glossed with a garlicky olive oil–butter finish. A simple, crowd-pleasing side or snack with big, savory flavor.
Preheat oven to 425°F (220°C).
Add 1.5 lbs yellow fingerling potatoes to a pot of heavily salted water; bring to a boil and cook until fork-tender, 10 to 15 minutes. Drain and shake well to remove excess water.
Spread potatoes on an unlined baking sheet. Using the bottom of a cup, smash each potato to about 1/4 inch (0.6 cm) thick.
Brush both sides with 2 tablespoons extra-virgin olive oil; season with 1/2 teaspoon fine sea salt and 1/4 to 1/2 teaspoon black pepper. Bake for about 25 minutes, until golden-brown.
In a small bowl, mix 2 tablespoons melted butter with 1 teaspoon garlic powder and 1/2 teaspoon onion powder.
Brush the tops of the roasted potatoes with the garlic-butter mixture; return to the oven and bake until the edges are crispy, about 10 minutes.
Garnish as desired (fresh herbs, flaky salt, Parmesan, or a favorite sauce) and serve hot.