Heat the plant-based milk in a saucepan for a few seconds until it’s lukewarm (not hot!), about 35–40°C (95–104°F). Add all the other ingredients for the yeast mixture and set aside for 5–10 minutes to activate the yeast. If it starts to get frothy, then the yeast is active.
Combine all the dry ingredients in a bowl and stir with a whisk.