Best Spaghetti With Sausage

Ingredients

• 1/2 pound lean ground beef
• 1/2 pound mild Italian pork sausage, ground or links with casings removed
• 1 small red onion, chopped
• 4 large cloves garlic, minced
• 1/2 teaspoon sea salt
• 1/2 teaspoon freshly ground black pepper
• 1 teaspoon red pepper flakes, optional
• 1 (32-ounce) carton low-sodium chicken broth or chicken stock
• 1 (24-ounce) jar marinara sauce
• 12 ounces spaghetti noodles
• fresh basil, to taste, chopped, for garnish
• parmesan cheese, to taste, grated, for garnish