Preheat the oven to 180°C (356°F).
Combine rice flour, baking powder, and salt in a bowl.
In a separate bowl, mix soy milk, vegetable oil, and maple syrup thoroughly.
Add the dry ingredients to the wet ingredients and mix until a thick batter forms.
Line a cake pan with parchment paper and pour in the batter, spreading it evenly.
Bake in the preheated oven for 30-35 minutes.
Let it cool completely, then remove from the pan.