In a medium skillet cook ground beef on medium high heat until no longer pink.
Drain and add in taco seasoning packet, diced onion, and garlic. Cook for another 3-4 minutes to allow spices to toast and onion soften. Set aside.
In a separate saucepan make cheese sauce. On medium heat whisk flour and ¼ cup of milk to make a rue.
Add in salt and paprika. Mix until a dough-like consistency forms.
Add in the remaining 1 cup of milk and stir until thickened.
Add in shredded Mexican cheese and stir until the cheese has completely melted. Set aside.
Preheat your oven to 400 degrees.
In an 9X13 aluminum pan begin assembling the lasagna.
First lay down four tortillas. You can tear them to fit the pan.
Next layer is the beef and onion mixture, layer 1 cup of mixture on tortillas.
Next add ½ cheese sauce and ½ cup of fresh salsa. Top with more tortillas.
Repeat these layers until the ingredients are gone and end with tortillas.
Top with shredded cheese and cover with foil.
Bake for 20 minutes.
Once done remove foil and bake for another 10 minutes.
Top with shredded lettuce, diced tomato, cilantro, and sour cream.