Preheat the oven to 350°F. Line a 9-inch cake pan with parchment paper.
To make the batter: In the bowl of a stand mixer fitted with the paddle attachment (or in a bowl with a hand mixer, or whisk), add the avocado oil, heavy whipping cream, cane sugar, and eggs. Mix on low until combined.
Add the cake flour, cocoa, vanilla bean, baking powder, and fine sea salt in that order. Mix on low until combined. Transfer to the prepared cake pan and spread evenly.
Bake at 350°F for 1 hour or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely in the pan.
To make the frosting: In the bowl of a stand mixer fitted with the paddle attachment (or in a bowl with a hand mixer, or whisk), add the buttter, powdered sugar, cocoa, heavy whipping cream, and vanilla extract. Mix on low until combined, then speed mixer up to high and whip for 1 minute or until light and fluffy.
Remove the cake from the pan and spread the frosting on top.
Serve immediately, or store in the fridge for up to 3 days.