Preheat your oven to 350°F (175°C).

Grease and line an 8x8-inch baking dish with parchment paper.

In a large bowl, whisk together the flour, cocoa powder, baking powder, baking soda, salt, and light brown sugar.

In another bowl, mix the dairy-free buttermilk, dairy-free yogurt, vegetable oil, and vanilla extract until smooth.

Add the wet ingredients to the dry ingredients and mix until just combined.

Gently fold in the grated courgette.

Pour the batter into the prepared baking dish and spread it evenly.

Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

Remove the sponge from the oven and allow it to cool slightly.

In a saucepan over medium heat, whisk together the dairy-free milk, sugar, and cocoa powder.

Bring the mixture to a simmer, stirring constantly, until the sugar is dissolved.

Add the vanilla extract and dairy-free butter, stirring until melted and combined.

Remove from heat and let it cool slightly.

While the sponge is still warm, poke holes all over the top using a fork or skewer.

Pour the warm chocolate fudge sauce over the sponge, allowing it to seep into the holes and soak into the cake.

Serve the pudding warm with a scoop of dairy-free ice cream or a drizzle of custard.