Pre-heat the oven to 350ºF.

Line a 8” or 9” springform cake pan with parchment paper and spray it with oil. If using a 8″ pan, make sure it’s deep. You can use a regular 9" cake pan.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set it aside.

In a large mixing bowl, or in the bowl of a stand mixer, beat the butter at medium speed for 30 seconds.

Add the granulated and brown sugar to the bowl, and beat together with the butter for another 2 minutes, until the mixture is light and fluffy.

Scrape the bowl every so often to ensure everything is getting nicely incorporated together.

Add the eggs, one at a time, mixing until incorporated before adding the next egg.

Add the vanilla and mix to combine.

Add the sour cream and mix until incorporated.

Add half of the dry ingredients to the bowl and mix on low to combine.

Pour the buttermilk in and mix.

Add the remaining dry ingredient mixture and mix on low to combine. You can also use the spatula instead of the mixer to fold the batter during this final stage. Avoid over mixing, to prevent the cake from turning out dry.

Spread the batter on the bottom of the prepared pan.

Bake the cake in pre-heated oven for about 40 to 45 minutes. If the top of the cake is browning too much towards the end, and the center is not yet cooked, cover it with a piece of aluminum foil.

You will know the cake is done baking when you touch the top of the cake and doesn’t feel soft or jiggly underneath. Insert a toothpick in the cake, and should come out clean, without any gooey batter attached.

Remove the cake from the oven and let it cool down completely.

When the cake has cooled down, use a dowel, or a chopstick, or even the handle of a wooden spoon or spatula, to poke holes in the cake.

Place 1/2 cup of cooled caramel sauce in a piping bag. Snip the end of the bag with scissors.

Pipe the caramel sauce inside each hole you poked. After a few minutes, the cake will absorb some of the caramel so you can pipe a bit more caramel in the holes to fill them up.

Place the cake in the fridge while you make the caramel cream cheese frosting.

Beat the butter with a mixer for 30 seconds. Add the cream cheese and beat for another 30 seconds.

Add the powdered sugar and caramel sauce and mix on low to combine.

Raise the speed to medium-high and beat for a few seconds until well incorporated. Scrape the bowl and mix again to combine.

If the frosting is too stiff, add a teaspoon of milk to make it thinner. And if the frosting is too runny, add a bit of powdered sugar to help it become thicker.

Spread the cream cheese frosting on top of the cake.

Drizzle about 1/4 cup of caramel on top of the frosting. But you don't have to do it all at once. First make a drizzle of one or two tablespoons of caramel, and use a spatula to swirl the caramel around with the frosting, creating beautiful waves.

Then you can repeat by drizzling the remaining caramel, and using the spatula again to form waves and swirls.

Sprinkle the top with sea salt.

Place the cake in the fridge for a couple of hours before serving, the cake will absorb some of the caramel, creating an incredible gooey texture.

You can make this cake ahead and serve even a dar after.

Let the cake sit at room temperature for about 20 minutes before serving so the butter in the cake and the caramel have a chance to soften up.

Store the cake in the fridge. Always cover the leftovers with plastic wrap, and place in an air tight container.

The cake can be stored in the fridge for up to 4 days, and in the freezer for up to 2 months.

Let the cake thaw in the fridge or in the counter.

Always let the cake come to room temperature a bit before serving.