Linguine and Tuna With Spicy Orange Sauce

Recipe is from the Washington Post.

• Ready In: 25 mins
• Serves: 4

Ingredients

•  kosher salt
• 8  ounces  dried whole-wheat linguine or 8  ounces spaghetti
• 1  leaf  from 1 bunch watercress (may substitute baby spinach)
• 2 (5 ounce) cans tuna packed in oil
• 2 -3  navel oranges
• 3  tablespoons olive oil
• 2  tablespoons  balsamic vinegar
• 2  tablespoons dijon-style mustard
• 3⁄4 teaspoon crushed red pepper flakes

Directions

1. Bring a large pot of water to a boil over high heat. Add a generous pinch of salt and the pasta; cook according to the package directions. Drain, reserving 1 cup of the cooking water.
2. Rinse and dry the watercress; you should have at least 1 1/4 cups. Drain and discard the oil from the tuna.
3. Finely grate the zest of 1/2 to 1 orange to yield 1 1/2 to 2 teaspoons, letting it fall into a large serving bowl. Cut that orange and the other(s) in half; squeeze them to yield 3/4 cup of juice; add 1/2 cup to the bowl, along with the olive oil, vinegar, mustard and crushed red pepper flakes, whisking to combine.
4. Add the watercress and the drained pasta, tossing to combine and coat evenly. Taste, and add some or all of the remaining orange juice, as needed; if the orange flavor is too prominent, use some of the reserved pasta cooking water to dilute the sauce.
5. Scatter the drained tuna over the pasta. Sprinkle with a small pinch of crushed red pepper flakes, if desired. Serve right away.