Basic White Cake

Ingredients

210 g pastry or all-purpose flour, 1 tsp baking powder, 1 tsp baking soda
1/2 tsp salt, 75 g vegan margarine, 200 g sugar, 150 g water, 2 tbsp vanilla, 1 tbsp apple cider vinegar

Preheat the oven to 350 F. In an 8-inch cake pan, line bottom of pan with parchment or wax paper, grease and flour paper and grease sides.
In a medium bowl, sift together the 210 g flour, 1 tsp baking powder, 1 tsp baking soda
In a separate smaller bowl, whisk 1/2 tsp salt, 75 g vegan margarine, 200 g sugar, 150 g water, 2 tbsp vanilla, 1 tbsp apple cider vinegar until blended.
Pour the wet mixture into the dry mixture, whisking until smooth. Pour the batter into the prepared cake pan.
Bake your cake in the preheated for 30 to 40 minutes, or until a toothpick inserted into the center comes out clean.
Cool the cake in the pan for 5 to 10 minutes, then carefully remove the cake from the pan to allow it to cool completely before frosting.

Because this vegan white cake has very little fat, you might also want to line the pan with parchment paper to prevent it from sticking. My first attempt stuck very badly, I forgot to use flour which might be enough to prevent sticking but I think using wax or parchment paper is probably for the best. Detailed instructions.
sifting flour in baked goods - usually not necessary, but some recipes do really need it:

There are times, however, when certain recipes actually benefit from sifted flour. The flour in cakes with a very light, delicate texture like genoise, angel food, or sponge should be sifted to eliminate and prevent lumps that would weigh down the batter.
vinegar in baked goods - used to to react with baking soda and start the chemical reaction needed to produce carbon dioxide and give those batters a lift as they bake.