Combine the dry ingredients in a large bowl and mix well. Sugar, flour, cocoa powder, baking powder, baking soda and salt.
In a second large bowl, combine the wet ingredients (except the water) and mix well. Eggs, milk, vegetable oil and vanilla.
Gradually add the dry ingredients to the wet ingredients. Add a third of the dry ingredients into the wet mixture and stir to combine. Add another third of the dry ingredients into the wet mixture and stir to combine. Add the remaining dry ingredients and stir to combine.
Add ¼ cup of water to the cake batter and stir to combine.
Spray the fluted baking pan with cooking spray and pour the cake batter into the pan.
Add 1 ½ cups of water to the inner pot.
Place the cake pan on the trivet and gently lower it into the pot.
Select PRESSURE COOK – HIGH and set the time for 35 minutes.
When the cooking time is completed, allow a 10 minute natural release, before carefully releasing the remaining pressure.
Carefully lift the cake out of the pot, place on a cooling rack and allow to cool.
Once the cake is completely cooled, flip it upside down and tap on it to release the cake.
Slice the cake in half, horizontally, and spread a thick layer of chocolate buttercream frosting on the bottom half.
Lay sliced strawberries on top of the frosting and place the top half of the cake on top of the strawberries.
Spread another layer of buttercream frosting on top of the cake and fill the center of the cake with sliced strawberries.
Using a hand mixer, beat the butter until light and fluffy.
Gradually add the powdered sugar and mix until the frosting is a smooth consistency.
Add the cocoa powder, cream, vanilla, and salt and mix until fully combined and the frosting is a smooth consistency.