Line top oven rack with heavy-duty aluminum foil. Make slits in the foil between every other grate, tucking the foil around and under the grate ridges. Preheat oven to 275 degrees Fahrenheit.

Moisten 10 paper towels slightly. Beginning and ending with a paper towel, create a stack of tortillas by placing one towel in between each tortilla, stacking them one on top of the other. Place the tortilla stack inside a zip-top bag and microwave for 30 seconds. Remove from microwave and discard paper towels.

Spray both sides of each tortilla with cooking spray. Make sure you coat the tortilla well. Sprinkle with sugar and cinnamon. On the top rack of your oven, drape each tortilla over two ridges, making sure that they’re draped evenly on each side. Place the rack in the oven and be sure to put a tray below the taco shells. (There will be sugar dripping from the tortillas.)

Leave the tortillas in the oven for 15–20 minutes or until they start turning golden brown. Remove the rack and allow the tacos to cool for about 10 minutes. They will harden while cooling.

Melt the margarine in a large, heavy frying pan over medium heat. Add the sugar and cook until it melts and turns a dark amber color. Do not stir until the sugar is completely melted. 

Add the apples, vanilla, and brandy and cook until softened and golden (but not mushy), and until the liquid at the bottom of the pan has almost completely evaporated, about 10 minutes. Sugar may crystallize when apples are added, but will liquefy again after a couple of minutes.

Preheat oven to 350 degrees Fahrenheit. In a medium-sized bowl, combine all ingredients until coarse crumbs form, and place in a 9- x 13-inch (20- x 30-centimeter) baking pan. Bake uncovered for 20 minutes.

Remove from oven and mix well, crushing the crumbs with a fork. Return to oven and bake an additional 15 minutes. Allow to cool and set aside.

In a small saucepan, melt caramel over medium heat. Add cinnamon, cognac, and vanilla, stirring well to combine. Keep warm for drizzling.

Place each taco on a plate, standing upright. Place three to four spoonfuls of warm apple filling inside each taco. Drizzle with caramel sauce and sprinkle with crumb topping, if using.

Best if served with vanilla ice cream. Try drizzling some additional caramel sauce and crumbs on top of the ice cream as well.