Chill the soy milk and the avocado oil (or other liquid oil of choice) in the fridge for at least 30 minutes;
Add all the butter ingredients except radishes in a blender cup, use either an emersion stick blender or your preferred blender to blend everything together, the mixture should become nicely emulsified in the process;
Set the butter mixture aside in the fridge for now;
Finely grate the radishes, transfer the grated shreds onto a cheesecloth or a nut milk bag, squeeze out as much liquid as you can, you can also use your hands if you don't have cheesecloth or milk bag. This step is to prevent excessive radish juice from turning the butter terrine mushy;
Take the butter base out, fold in the grated radish evenly, and transfer into your mold;
If you'd like to decorate the top of the terrine, lay down a layer of thinly sliced radish first;
Cover and let it set in the fridge for 6 hours, or leave it overnight;
Serve with toast, croissant, or even steamy rice (trust me it's so good!), enjoy!