Whole-Wheat Spaghetti with Swiss Chard and Pecorino Cheese

Prep Time: 20 mins Cook Time:20 min Serves: 4 servings Ingredients 1 tablespoon olive oil 2 onions, thinly sliced 2 bunches Swiss chard, trimmed and chopped (about 14 cups) 3 garlic cloves, minced 1 (14 1/2-ounce) can diced tomatoes with juices 1/4 cup dry white wine 1/4 teaspoon dried crushed red pepper flakes Salt and pepper 8 ounces whole-wheat spaghetti …