You will need a large frying skillet, cast iron is great. A cheese grater, and a large shallow bowl. Bakes in a 9x12 glass casserole dish.
First take the frozen shrimp and start to soak them in a water to thaw them. I just put them in the same aluminum sauce pan that will be used to cook them later.
Instructions:
This always takes me over an hour, moving slowly and often watching TV (Food Network) at the same time.
Heat some canola oil in a large skillet. Spray your 9x12 glass casserole dish with some non stick olive oil. Pour half the can of red enchilada sauce in a large shallow bowl.
Cut all 12 tortillas in half (half-moons),. Set half of them aside for later. (12 halves)
Fry the first (12) halves of tortillas for about 10 seconds each, then using tongs dip them in the bowl of red enchilada sauce. Coat both sides and line the bottom of your casserole dish. When lined, added 1/3 of the Queso Fresco cheese (fresh grated), 1/3 of the onion (diced).
Take your pan of thawed shrimp, peel and rinse them, then put on a hot burner for 4-6 minutes. Do not boil, as shrimp do not need to be fully cooked. YOu want them just starting to turn pink. They will cook through when baking. Lay shrimp out on top of the 1st layer in your casserole dish.
Top shrimp with another 1/3 of freshly grated Queso, and 2nd 1/3 onion. This fills in the gaps around the shrimp.
Then fry, dip and layer the remaining tortillas on top. Top with last 1/3 cheese, last 1/3 onion, and remaining 1/2 can of red enchilada sauce (and what remains in dipping bowl).
Bake for 20-25 minutes at 375 or until cheese is starting to brown.
When serving, you can most certainly top it with dabs of sour cream, fresh squeezed lime juice, chopped California green onions and or fresh sliced avocado.