Helpful Tips about Caramelized Onions.

• Make-ahead tip.  Make caramelized onions ahead of time, refrigerate them in an air-tight container, and use within the next 3 days.
• You can also freeze caramelized onions for up to 2 months and thaw them whenever you need them.

Substitutions for heavy cream

• Half-and-half. You can use 1 cup of half-and-half instead of heavy cream.  Bring half-and-half to boil, then add 1/s cup of shredded Parmesan cheese.  Reduce to simmer.  Keep stirring while the sauce simmers until the cheese melts.
• Coconut milk. Use 1 cup of coconut milk to replace 1 cup of heavy cream.  Follow the recipe as is.

Other Substitutions 

• Use button mushrooms, portobello, cremini, shiitake or oyster mushrooms.
• Good substitutes for spinach are kale and arugula.
• You can also use pre-made ravioli, gnocchi or short pasta (such as bow-tie or penne pasta) instead of tortellini.
• Substitute tortellini with gluten-free ravioli or gluten-free short pasta, such as gluten-free bow tie pasta.  You can also use gluten-free gnocchi (be sure to check the packaging as not all gnocchi is gluten-free).
• Protein.  You can add grilled steak, pork chops, or chicken.  You can also serve this with fish, shrimp, or scallops.