Classic Spanish Torta

1. Cut potatoes lengthwise into quarters; cut quarters crosswise into 1/8-inch-thick

slices to measure 4 cups.

2. In large saucepan, combine potatoes and onion; add canola oil and 1/2 cup olive oil, adding more oil, if necessary, until vegetables are covered. Season with salt.

3. Place saucepan over low heat and cook until vegetables are tender, 30

to 40 minutes. Remove from heat; drain vegetables, reserving oil. Set vegetables aside. Carefully strain oil through a fine-mesh strainer; refrigerate for another use.

4. Heat 2 tablespoons olive oil in 10-inch nonstick skillet over high heat. Meanwhile, in large bowl, beat eggs with 1/2 tablespoon salt just until blended. Fold reserved potatoes and onion into eggs to combine.

5. When oil is smoking, swirl up sides of pan to prevent from sticking. Pour egg mixture into pan and toss aggressively (as if sautéing it or flipping pancakes), about three times.

With spatula, begin to shape sides of tortilla by pulling mixture gently from sides of pan, shaking the pan to avoid sticking. When eggs just begin to set, after about 1 minute, reduce  heat to medium-low; cook 2 more minutes.

6. Invert tortilla onto large plate and place pan back on burner; wipe pan clean

and recoat it with remaining 1 tablespoon olive oil. Heat the oil over high heat until it begins to smoke; quickly slide tortilla off plate and back into pan. Cook for 1 minute. Repeat the flip-and-return process and reduce the heat to very low. Cook for another 2

minutes; flip back onto plate. Repeat process until bottom and top of tortilla are golden and eggs are cooked through.

7. Let stand at room temperature until ready to serve. Cut into wedges. Accompany with sauce, if desired.