Preheat the oven to 350°F (175°C). Line a large cookie sheet with parchment paper and set aside.

In a large bowl, cream together 1 cup unsalted butter (room temperature) and 1 cup white granulated sugar with an electric mixer on medium speed for about 3–4 minutes, until light and fluffy.

Add 2 egg whites and 1 teaspoon vanilla extract to the butter-sugar mixture and mix until well combined.

Add 3 cups all-purpose flour and 1 1/2 teaspoons baking powder. Mix on low speed until the dough is just combined and no large streaks of flour remain.

Turn the dough out onto a lightly floured surface. Roll the dough to a 1/4-inch thickness.

Use a round cookie cutter to cut out cookie circles and transfer them to the prepared parchment-lined cookie sheet, spacing them about 1 inch apart.

Bake for 6–8 minutes, or until the cookies are puffy, no longer glossy on top, and the edges are just turning golden. Remove from the oven and cool on the pan for 5 minutes.

Transfer the cookies to a wire rack and cool completely before topping.

While the cookies cool, place 20 unwrapped caramels and 1 tablespoon heavy cream in a microwave-safe bowl. Microwave in 30-second intervals, stirring well between each interval, until the caramels are melted and the mixture is smooth and creamy.

Spoon about 2 tablespoons of the warm caramel onto the center of each cooled cookie and spread it nearly to the edges. Refrigerate the topped cookies for 10–15 minutes, or until the caramel is fully set.

Place 1 1/2 cups milk chocolate chips (or chopped Ghirardelli milk chocolate baking bar) in a microwave-safe bowl. Microwave in 30-second intervals, stirring well between each interval, until the chocolate is fully melted and smooth.

Spoon or spread a small amount of the melted chocolate over the set caramel on each cookie to cover the caramel layer.

Let the chocolate layer set completely before serving (allow to sit at room temperature until firm, or chill briefly to speed setting).