Double-frying is the trick to these creamy-on-the-inside, crisp-on-the-outside potatoes. The second dip in hotter oil browns them and crisps the outside.
- 2 tablespoons extra-virgin olive oil plus more for frying
- 1 small yellow onion (1/2 cup), chopped
- 1 tablespoon smoked Spanish paprika (such as Pimentón de La Vera Dulce)
- 1 tablespoon hot smoked Spanish paprika (such as Pimentón de La Vera Picante)
- 1 tablespoon all-purpose flour
- Kosher salt, freshly ground pepper
- 2 pounds russet potatoes, peeled, cut into 1-inch cubes
Heat 2 Tbsp. olive oil in a small saucepan over medium heat. Add onion and garlic and cook, stirring often, until translucent, about 8 minutes. Add bay leaf and next 3 ingredients and cook, stirring constantly, for 2 minutes. Stir in 1 1/2 cups water and bring to a boil, whisking constantly. Reduce heat to low and simmer until flavors meld, about 10 minutes. Remove bay leaf, season with salt and pepper, and purée in a blender. Set aside.
Attach deep-fry thermometer to the side of a large heavy pot. Pour oil into pot to a depth of 2 inches. Heat over medium-high heat until thermometer registers 225°. Add the potatoes and cook, stirring occasionally and adjusting heat to maintain temperature, until tender, about 10 minutes. Using a slotted spoon, transfer potatoes to a platter; let cool completely.
Heat oil to 350°. Working in batches, add cooled potatoes and cook until golden brown and crisp, 5–7 minutes. Transfer to paper towels and season with salt. Rewarm sauce. Serve potatoes with sauce.