I discovered this recipe a few months ago, and it is a favorite in my house. Variations of this recipe can be found under other names, including Mexican Lasagna and Mexican Pie. You can make the recipe as written. But I rarely follow directions to the letter and like to add my personal touch. This recipe is very forgiving to changes, so feel free to experiment. I suggest you read the reviews of people who have made it. They have great ideas and suggestions.
For this recipe I do the following changes/additions:
Add ground beef mixed with a packet of taco seasoning
Add homemade Spanish rice (I posted the recipe in a past Musing-you can look it up)
I use the refried beans straight from the can, I do not pan fry it.
Saute the onions (without the refried beans)
I also like to mix a can of cream of chicken soup with salsa and spread that on the top prior to baking.
Link to the recipe:
http://allrecipes.com/Recipe/Mexican-Casserole/Detail.aspx?event8=1&prop24=SR_Title&e11=mexican%20casserole&e8=Quick%20Search&event10=1&e7=Home%20Page&soid=sr_results_p1i3