First, in a large mixing bowl, whisk together the flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt until well combined.

In a separate bowl, whisk together the buttermilk, avocado oil, eggs, and vanilla extract until smooth.

Gradually pour the wet ingredients into the dry ingredients, stirring until just combined. Be careful not to overmix.

Add the hot water to the batter and stir until the batter is smooth.

Lightly grease a 7-inch cake pan that fits inside your Instant Pot with cooking spray. Pour the cake batter into the prepared pan.

Pour 1 cup of water into the inner pot of your Instant Pot. Place the trivet inside the pot. Cover the cake and cake pan with tin foil. Create a foil sling that wraps under the cake so you can easily lower it into the pot.

Carefully lower the cake pan onto the trivet inside the Instant Pot. Use the aluminum sling to help you.

Close the lid of the Instant Pot and set the valve to the sealing position.

Select the “Manual” or “Pressure Cook” setting and set the cooking time to 35 minutes on high pressure.

Once the cooking time is complete, allow the pressure to release naturally for 10 minutes. Then, perform a quick release to release any remaining pressure.

Carefully remove the cake pan from the Instant Pot and let it cool on a wire rack for about 10 minutes. Then, remove the cake from the pan and allow it to cool completely.

While the cake is cooling, prepare the frosting. In a mixing bowl, cream together the softened butter, powdered sugar, cocoa powder, milk, and vanilla extract until smooth and creamy.

Once the cake has cooled, frost the top and sides with the prepared frosting.

Finally, serve and enjoy!