12 ounces casarecce or fusilli pasta
1 (28-oz.) can diced tomatoes
2 cups chicken broth
1/2 medium-size yellow onion, sliced
4 garlic cloves, sliced
1 teaspoon dried oregano
1/3 cup firmly packed fresh basil leaves
2 teaspoons kosher salt
1 tablespoon olive oil
1/4 teaspoon dried crushed red pepper (optional)
1 (6-oz.) package baby spinach
Freshly grated Parmesan cheese
Place first 9 ingredients and, if desired, dried crushed red pepper in a Dutch oven in order of ingredient list.
Cover and bring to a boil over medium-high heat (about 12 to 15 minutes).
Reduce heat to medium-low, and cook, covered, 10 to 12 minutes or until pasta is slightly al dente, stirring at 5-minute intervals.
Remove from heat, and stir in spinach. Cover and let stand 10 minutes. Stir just before serving. Serve with Parmesan cheese.