Creamy Sausage Tortellini Soup

Ingredients

• 1 tablespoon olive oil
• 1 pound Italian sausage (mild or spicy, according to taste)
• 1 small onion, diced
• 2 cloves garlic, minced
• 4 cups chicken broth
• 1 can (14.5 ounces) diced tomatoes, undrained
• 1 teaspoon Italian seasoning
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1 package (9 ounces) refrigerated cheese tortellini
• 2 cups fresh spinach
• 1 cup heavy cream
• 1/2 cup grated Parmesan cheese
• Fresh basil, for garnish (optional)