Preheat your oven to 350°F (175°C), line and grease three 8-inch round cake pans with parchment paper.

In a mixing bowl, whisk together gluten-free flour blend, cornstarch, baking powder, and kosher salt.

In a measuring cup, combine milk, heavy cream, and vanilla extract, whisk until blended.

In a stand mixer, beat softened butter and granulated sugar until light and fluffy, then add eggs one at a time.

Gradually add the dry mixture to the creamed butter and sugar, alternating with the wet mixture.

Let the batter rest for 15-20 minutes to enhance texture.

Pour batter into prepared pans and bake for 45-50 minutes or until a toothpick comes out clean.

Let the cakes cool in the pans for 10 minutes before transferring to a wire rack.

In a saucepan, combine heavy cream, light brown sugar, corn syrup, and flake salt, stir over heat until boiling.

Cook until mixture reaches 234°F, stirring continuously to prevent burning.

Remove from heat, stir in vanilla extract, and let cool for 5-10 minutes.

Spread caramel on top of the first cake layer, repeat with the second layer and add the final layer.

Pour remaining caramel over the top, allowing it to drip down the sides.