Preheat oven to 400°F (200°C).

Melt 2 tablespoons of butter in a small bowl. In a separate shallow dish, combine granulated sugar and 1 tablespoon of ground cinnamon.

Brush both sides of each tortilla with melted butter and dredge through the cinnamon-sugar mixture until evenly coated.

Place the tortillas over two bars of an oven rack (draping them to form a U-shape) or fit them into the gaps of an inverted muffin tin. Bake for 5 to 7 minutes until crisp. Set aside to cool and harden.

In a large skillet over medium heat, melt the remaining 2 tablespoons of butter. Add the diced apples, brown sugar, remaining 1 tablespoon of cinnamon, and lemon juice.

Cook for 8 to 10 minutes, stirring occasionally, until the apples are tender.

Whisk the cornstarch and water together in a small bowl to create a slurry. Pour the slurry into the skillet with the apples.

Stir continuously for 1 to 2 minutes until the sauce has thickened and become glossy. Remove from heat.

Spoon approximately 2 tablespoons of the warm apple filling into each prepared taco shell.

Top with whipped cream and a drizzle of caramel sauce immediately before serving.