Brown ground beef with taco seasoning.
While that’s cooking, chop onion, spinach, bell peppers & mushrooms.
Place ground beef into freezer safe gallon size bag
Mix together black beans, salsa, corn, spinach, onions, peppers and mushrooms.
Put in another gallon size freezer safe bag.
Label both bags and lay flat to freeze
Get bags out of freezer the night before you plan to assemble this meal so they are able to be layered in the morning.
Layer ingredients in bottom of slow cooker in the following order at a time: tomatoes, tortillas, ground beef, Vegetable/bean mixture, cheese.
End with layer of tomatoes & cheese
Cook on low 4 hours
Top with avocados & sour cream