In a skillet, cook the beef until brown. Add in taco seasoning and mix well to combine. Set aside
Place about ½ cup of beef onto a tortilla, top with about 2 tbsp of shredded cheese
Top with a tostada shell and add sour cream
Add diced tomatoes and shredded lettuce
At this point, you can take a large cookie cutter or just cut a circle out of an extra tortilla to place on top so nothing falls out. This is an optional step, but I find it helps hold the wrap together better
Take the bottom tortilla and fold it around the filling
Warm up a griddle or skillet and place the wrap with the folds facing down. Leave on the skillet until golden brown. This will help the tortilla keep its shape and melt the cheese