Creamy Spinach Tomato Tortellini

Ingredients

• 1 (20 oz) pkg three cheese tortellini (preferably the refrigerated kind)
• 2 Tbsp butter
• 2 cloves garlic, minced
• 3 Tbsp all-purpose flour
• 1 tsp onion powder
• 1 1/4 cups milk (I used 2%, anything but skim works fine)
• 1/2 cup heavy cream
• 1 (14.5 oz) can petite diced tomatoes (undrained)
• 1 1/2 cups (packed) chopped fresh spinach
• 3 Tbsp chopped fresh basil
• 2 tsp chopped fresh oregano (or 1/2 tsp dry)
• Salt and freshly ground black pepper
• 6 Tbsp finely shredded parmesan, plus more for serving
• Red pepper flakes, for serving (optional)