Preheat your oven to 325°.
In a standing mixer fitted with the paddle attachment, add the butter and both sugars. Mix on high speed until the mixture is light and fluffy, about 5 to 7 minutes.
Add the eggs one at a time, ensuring each is fully incorporated before adding the next.
In a separate bowl, whisk together the flours, baking soda, baking powder, and sea salt until combined.
Gradually add half of the dry mixture to the creamed butter and sugar, mixing on low speed until just combined.
Now, add in the sour cream and mix until just combined.
Incorporate the remaining dry ingredients, mixing gently.
Transfer the batter into a 10-cup bundt pan and bake for 60 to 70 minutes.
Allow the cake to cool in the pan for 20 minutes before inversion onto a cooling rack.
Prepare the caramel sauce by mixing all ingredients in a medium pot over medium heat.
Pour the caramel over the cooled bundt cake.