Brown 1 pound of lean ground beef with diced onion, diced red bell pepper and diced garlic until beef is in tiny crumbles with no pink remaining and vegetables are tender
Drain off all the grease and season with coarse salt, pepper and taco seasoning packet
Stir in ⅓ cup of water and let simmer for a couple minutes to thicken
Lightly brush a 9 by 13 casserole dish with melted butter on the bottom and sides
Arrange five burrito size flour tortillas around the edges and bottom of the dish, making sure it's completely covered with excess hanging over
Sprinkle with 2.5 cups of shredded Mexican blend cheese
Add fully drained can of Rotel (diced tomatoes with chilies)
Dollop 8 ounces of sour cream on top of the Rotel
Add 8 crunchy tostada shells, overlapping them to fit
Pour 1 cup of nacho cheese sauce over the tostada shells
Spread the beef mixture in an even layer
Place the remaining tortilla in the center and wrap the overhanging tortillas over the top to fully enclose the casserole
Brush the top with melted butter and press down on any loose ends
Bake uncovered at 375 degrees for 30 minutes until golden brown and lightly toasted
Let stand 5 to 10 minutes
Carefully invert onto a serving board and cut into squares
Serve with shredded lettuce, sour cream, guacamole and hot sauce
