Creamy Chicken Tortellini Soup

Ingredients

• 4 tablespoons butter
• 1/2 teaspoon crushed red pepper flakes
• 1/2 teaspoon herbs de provence
• 1 large onion, diced (about 1 1/2 cups)
• 1 sweet red bell pepper, diced
• 2 large carrots, chopped in 1/2-inch pieces (a heaping cup)
• 2 long celery stalks, diced (a heaping cup)
• 6-8 cloves garlic, thinly sliced or minced
• 1 tablespoon fresh sage, chopped
• 5 sprigs fresh thyme, chopped
• 1/4 cup all purpose flour
• 6 cups good quality chicken stock (plus more if needed to adjust consistency)
• 2 bay leaves
• 1/2 teaspoon onion powder
• 1/8 teaspoon cayenne pepper
• 12 to 16 ounces fresh cheese tortellini (SEE NOTE)
• 1 cup heavy cream or half and half
• 1 5-oz bag fresh baby spinach
• 2 cups shredded rotisserie chicken (SEE NOTE)
• 1/4 teaspoon freshly ground nutmeg (SEE NOTE)
• 2 teaspoons white wine vinegar or lemon juice (optional)
• Zest from one lemon
• Flaky kosher salt, to taste
• Freshly ground black pepper, to taste