Preheat your oven to 350°F (175°C) and prepare three 8-inch round cake pans by greasing them and lining with parchment.

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

In a separate cup, mix the milk, heavy cream, and vanilla extract until blended.

In a stand mixer, cream together softened butter and granulated sugar until light and fluffy, about 3-5 minutes. Add eggs one at a time.

Gradually add the dry ingredients to the creamed mixture, alternating with the milk mixture.

Cover the batter and let it rest for 15-20 minutes.

Divide the batter among the prepared cake pans and bake for 45-50 minutes.

Cool the cakes in the pans for 10 minutes before transferring to a cooling rack.

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

Boil until the mixture reaches 234°F (113°C), stirring constantly.

Remove from heat and stir in vanilla extract; allow caramel to cool slightly.

Assemble the cake by layering with caramel between the cake layers and drizzling it over the top.