Preheat your oven to 350°F (175°C).
Grease and line three 8-inch round cake pans with parchment paper.
In a large bowl, whisk together the flour, granulated sugar, light brown sugar, cocoa powder, baking powder, baking soda, and salt.
In another bowl, mix the dairy-free yogurt, buttermilk, melted coconut oil, and vanilla extract until smooth.
Add the wet ingredients to the dry ingredients, mixing until just combined.
Gradually add the hot water, mixing until the batter is smooth.
Divide the batter evenly among the prepared pans.
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.