Heat the plant-based milk in a saucepan for a few seconds until it's lukewarm (not hot!) about 35-40 degrees C (95-104 degrees F). Add yeast, sugar, and olive oil and set aside for about 10 minutes to proof the yeast. If it starts to get frothy, then the yeast is still active and usable.
Combine all dry ingredients (flour, psyllium husk powder, sea salt) in a bowl and stir with a whisk.
Add the yeast mixture and stir with a wooden spoon. It might seem too wet in the first few seconds but that will change within a minute. Knead the dough for about 5 minutes with your hands (it will be sticky, that's ok), form a dough ball and set aside (preferably in a warm place) for about 60 minutes. It should almost double in size.
Once the dough has risen, place it on a floured surface, and roll it out with a rolling pin about 0.6-0.8 cm thick. It should have a diameter of about 30 cm (12 inches).
Preheat oven to 200 degrees C (390 degrees F).
Line an 8-inch springform with parchment paper or grease it with some oil. Carefully place the dough into the springform. It should look like this. Let it rest again for about 10 minutes.
Pre-bake the dough for around 10 minutes. Meanwhile, you can chop the veggies.