Preheat the oven to 325 degrees F.

Grease and flour two, 8-inch round cake pans and set aside.

Make sure to set the cold ingredients out, so they can come closer to room temperature before making the batter. This will keep the batter from clumping up and will help it mix better.

In a medium-sized bowl, combine the flour, baking powder and salt. Whisk well and set aside.

In another bowl, sour cream, milk, and vanilla extract. Whisk well and set aside.

In a large mixing bowl, add the room-temperature butter, oil and the sugars and mix with an electric mixer on medium-high for several minutes until light and fluffy.

Add the eggs one at a time, and mix on low-medium but only for about 15-20 seconds after adding each egg.

Scrape down the sides and bottom of the bowl and mix again on medium for another 10 seconds.

Add half the dry ingredients to the butter mixture. Mix only on medium and only until it’s just combined and you don’t see any dry flour.

Add the liquid ingredients and mix on medium only until just combined. Mixing too long once you add the liquid, will make the cake very dense. Only mix until just combined.

Remove the cake layers from the oven and place them on a wire rack, still inside the pans, for about 15 minutes. The cake layers will flatten out a bit as they cool. That’s okay.

After 15 minutes turn the cake layers out of the pans and set them onto the cooling racks and allow them to cool completely before adding filling and frosting.

Melt the butter and the brown sugar in a saucepan over low-medium heat until melted. Turn up the heat to medium-high and bring the mixture to a boil and boil for two minutes, stirring constantly.

Add the cream and bring to a boil again, but take off the heat when it reaches a boil.

Once it’s removed from the heat, add the vanilla extract, stir it in, then let it sit for about 5 minutes or so.

Add the sifted confectioner’s sugar and mix until smooth using a spoon or a whisk. A whisk will help smooth out any lumps of confectioner's sugar that may occur.

If there are still lumps of confectioner's sugar, mash it through a metal strainer while it’s still hot to remove them.

Frost the cake with the slightly warm caramel. If it’s too warm, it will slide off the cake, so just experiment with the temperature when adding it to the cake. If too warm, just let it sit and set up a little more, stirring occasionally.

Also, the frosting will set up fast while frosting the cake, so you’ll need to move quickly. If it sets up too much, just pop it in the microwave for about 10 seconds at a time, mix again, then continue to add to the cake. Don’t worry about getting the frosting on the cake perfectly. That’s not going to happen with a caramel frosting like this. The nature of caramel frosting is just messy, so don’t worry about striving for perfection here. Cakes that look homemade and rustic are some of the best cakes there are, so it’s okay.