Add two tortillas to the prepared pan. Cut 1 tortilla into quarters and add each quarter to the corners of the pan, to cover any empty spaces there. Cut 1 tortilla in half, and add each half to each side of the pan, straight side touching the pan and covering the empty space.
Add half of the refried beans and carefully spread them on top of the tortillas, trying to avoid moving the tortillas.
Add half of the beef mixture and spread it evenly.
Add half of the black or pinto beans, on top of the beef mixture.
Top with 1 1/2 cups of shredded Mexican blend cheese.
Repeat with another layer of tortillas, remaining refried beans, remaining beef mixture, remaining black or pinto beans and 1 1/2 cups cheese.
Top with another layer of tortillas, spread 1 cup of salsa over the final layer of tortillas and sprinkle 1 cup of shredded Mexican blend cheese.