Preheat the oven to 350 degrees F (175 degrees C). Lightly grease a 9x12-inch baking pan.
Combine flour and baking soda in a bowl.
Combine sugar, oil, and vegan butter in a food processor and process until light and fluffy, about 2 minutes. Add tofu and process until combined, about 2 minutes more. Mix in cocoa powder and vanilla extract. Add flour mixture, a few spoonfuls at a time, processing after each addition. Transfer to a bowl and stir in chocolate chips, walnuts, and coconut. Pour into the prepared pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 25 minutes.