Preheat your oven to 350°F (175°C).
Line your 9x13-inch baking pan with parchment paper, leaving some overhang on the sides.
In a large mixing bowl, combine the butter, granulated sugar, and powdered sugar. Beat until light and fluffy, about 2-3 minutes.
Add the vanilla extract and beat until incorporated.
Gradually add the flour and mix on low speed until just combined.
Transfer the dough into the prepared baking pan and spread evenly.
Bake for 20-25 minutes, until edges are golden and center is set.
Allow the base to cool for about 10 minutes.
Prepare the caramel layer by melting caramel candies with a splash of milk in a saucepan over low heat.
Pour the caramel over the cooled base and spread evenly.
Bake again for 10-15 minutes until caramel is bubbly and set.
Cool completely on a cooling rack before lifting out and cutting into squares.
