Step 1

Preheat the oven to 350°F (180°C).

Step 2

Spray a 10×15 half sheet baking sheet with non-stick spray. Set aside.

Step 3

Sift the flour into a mixing bowl and add the sugar, baking soda and salt.

Step 4

Then add the soy milk, vanilla, oil and vinegar.

Step 5

Use a hand whisk to mix in. Be careful not to overmix the batter, just mix until all the large lumps are gone, tiny lumps are fine.

Step 6

Pour the batter out into your prepared half sheet baking pan.

Step 7

Spread the batter with the back of a spoon so that it reaches the corners of the baking sheet and is evenly distributed across it.

Step 8

Place into the oven and bake for 20 minutes or until a toothpick inserted into the center comes out clean.

Step 9

Place onto a cooling rack to cool completely before frosting.

Step 10

Prepare your frosting by adding the powdered sugar, vegan butter, soy milk (see notes), vanilla, and food coloring (if using) into the bowl of an electric mixer. Start at slow speed and gradually increase speed until your frosting is thick and smooth. If your frosting is too thin, add more powdered sugar, if it’s too thick, add more soy milk a drop at a time until it reaches the right consistency.

Step 11

Frost the cooled cake and decorate with sprinkles.

Step 12

Cut into squares and serve.