Step 1: Preheat your oven to 350°F (175°C). This ensures your cake will bake evenly.
Step 2: In a large mixing bowl, whisk together the all-purpose flour, sugar, salt, and baking soda until well combined.
Step 3: In another bowl, combine the water (or plant-based milk), oil, white vinegar, and vanilla extract. Whisk until the mixture is smooth.
Step 4: Pour the wet ingredients into the dry ingredients. Mix gently until just combined. Be careful not to overmix; a few lumps are okay.
Step 5: Fold in the sprinkles, if using.
Step 6: Divide the batter evenly between the prepared cake pans. Bake for 30-35 minutes or until a toothpick inserted comes out clean.
Step 7: Let the cakes cool in the pans for about 10 minutes, then transfer to a cooling rack to cool completely.
Step 8: In a mixing bowl, beat together the softened vegan butter and vegan cream cheese until smooth. Gradually add the powdered sugar until light and fluffy.
Step 9: Once cooled, frost the first layer, place the second layer on top, and frost the top and sides. Decorate with sprinkles if desired.