Preheat your oven to 375° F (190° C). (You will turn it down to 350° F once you put the cake in, but this initial hotter temperature helps the cake to rise.)
Prepare two round cake pans (8″- 9″ work well) by spraying them will oil and place a cutout circle of parchment paper at the bottom of the pan).
Measure the dry ingredients into a large mixing bowl and give them a little stir with a whisk. (Be sure to spoon measure the flour.)
Add the oil, vanilla, and 1/2 of the carbonated water to the dry ingredients and stir with a whisk until you have a smooth thick batter.
Stir in the remaining carbonated water and the vinegar and stir again just enough to form a smooth batter. (Don't over mix.)
Pour into the prepared cake pans.
Place the cakes in the oven, turn down the heat to 350° F, and bake for 30-35 minutes at 350° F until the top center appears dry and springs back up when touched.
Allow it to cool for 30 minutes in the cake pan then invert them onto a plate in the refrigerator to cool completely before frosting.
Assemble the sponge cake
Put your first cake top side down on your serving dish. (If you have a very round top, you may want to trim it so it's flat on top.
Arrange fresh sliced strawberries on top of the first layer, then put a thick layer of buttercream (or whipped cream) on top of the strawberries.
Put your next layer on the top right side up.
Sprinkle the top of the cake with a dusting of powdered sugar. (Put the powdered sugar in a wire mesh strainer and hold it over the cake tapping it lightly sprinkle the sugar on top.)
Notes
Spoon measure the flour. This simply means to fill the measuring cups with spoonfuls of flour and not pack the flour down when measuring. This will ensure you are measuring the correct amount of flour.
Don't over stir the cake batter. You don't want to stir out the bubbles.
Preheat the oven to 375° F (190° C) even though you are going to be baking it at 350° F (176°F). This initial hotter temperature helps the cake to rise. I do this trick will all of my muffin recipes too for a nice muffin top.
If you are using vegan whipped cream, assemble the cake immediately before serving.