In a skillet or in the pot on Brown/Saute, brown the beef with the onion and garlic. Drain the fat, if necessary. Add the corn, 2 tbsp taco seasoning and beef broth. Simmer for a few minutes. Remove from the pot and place in a large bowl.
On medium heat (low if using Brown/Saute) add the flour to the empty pot. Slowly whisk in the milk and continue cooking until the sauce is thickened. Add the meat mixture back into the skillet/pot with the sauce and simmer for 5 minutes.
In a separate bowl (use the same one that you used for the meat mixture,) mix the refried beans, tomato sauce and 1 tbsp taco seasoning until blended well.
In a 7" springform pan, layer: tortilla, meat mixture, tortilla, bean mixture, cheese, tortilla, etc. until the pan is full. Top with cheese and cover with foil. Repeat in another pan for the second pie. Place the second pie in the freezer if you don't plan to cook it right away.
Add 1 cup water to the pot. Using a trivet with handles, lower the pan into the pot. Close and lock the lid, turning the steam release valve to closed. Press Steam and adjust time down to 5 minutes. Press Start/Stop.
When cooking timer is done, flip the steam release valve open to do a quick pressure release. Lift out the pan and let it set for 5-10 minutes. Cook the second pie while the first one sets. Unlatch the pan and remove the outside. Slice like pie and serve with guacamole, sour cream, salsa or whatever you like!
Mexicorn is just regular canned corn mixed with red and green peppers. If you can't find it, use a can a corn and add a can of Rotel for extra flavor and a little heat. If freezing one pie, reheat it from frozen in the oven at 350 for 60 minutes, or until warmed through.