Start by preheating your oven to 350°F (175°C). Grease two 9-inch cake pans and line the bottoms with parchment paper. This helps them release easily later.

In a clean mixing bowl, pour in the aquafaba and add the cream of tartar. Using a mixer, whip on high speed until it forms soft peaks this usually takes about 3–5 minutes. It’ll look a bit like whipped egg whites.

In a separate large bowl, beat the softened vegan butter, canola oil, and sugar together until it’s creamy and light – about 2–3 minutes. Don’t rush this part; creaming helps with the cake’s texture.

Mix in the vanilla extract and apple cider vinegar. The vinegar will react with the baking powder later to help the cake rise.

In another bowl, sift together the cake flour, baking powder, and salt. Sifting is key here to keep the cake fluffy.

Now, alternate adding the dry mixture and soy milk into the creamed butter mixture — start and end with dry. Stir gently after each addition until just combined. Don’t overmix.

Carefully fold the whipped aquafaba into the batter. Use a spatula and mix gently to preserve the fluffiness. Your batter should look airy and smooth.

Divide the batter evenly between your two cake pans. Tap them lightly on the counter to release air bubbles. Bake for 30–35 minutes or until a toothpick comes out clean from the center.

In a bowl, beat the vegan butter until creamy. Gradually add the powdered sugar, vanilla extract, and soy milk. Keep mixing until light and fluffy. If it’s too thick, add a bit more milk; too thin, add more sugar.

Once your cakes are cooled, frost the top of one layer, place the second cake on top, then frost the top and sides. Decorate however you like!