Preheat the oven to 350°F (180°C). Spray two 7-inch round cake pans (*see notes) with non-stick spray and cut parchment paper into circles to fit the bottoms.
Sift the flour into a mixing bowl and add the sugar, baking soda and salt. Mix together.
Add the soy milk, vanilla, oil and vinegar and give it a quick whisk with a hand whisk until just combined.
Divide the batter evenly between your two prepared cake pans.
Bake for 25-30 minutes or until a toothpick inserted into the center of one of the cakes comes out clean.
Let the cakes cool in the pans for a few minutes before transferring them to a wire cooling rack to cool completely.
Prepare your frosting. Add the powdered sugar, vegan butter, vanilla and half of the soy milk.
Beginning on low speed, mix with an electric mixer, slowly increasing speed. Add the rest of the soy milk, only as much as needed until it is smooth and creamy. If your vegan butter has a higher water content, you may not need to use all of the soy milk.
If your frosting is still a little thin, add more powdered sugar, if it's a little thick, add more soy milk (a drop at a time). The consistency must be thick enough that it doesn't slide off the cake, but thin enough to be spreadable.
When your cake is completely cool, add frosting to the top of one of the layers.
Add the second layer on top and frost it completely, using a knife to carefully frost the sides of the cake.
Decorate with fresh strawberries and serve right away.
If you're not serving right away, then omit the strawberries or serve them on a plate alongside the cake, so it doesn't get soggy.