Preheat oven to 350°F/180°C.
Make sauce. Cook potato and onion by boiling until soft. Place all sauce ingredients into a high speed blender and blend until smooth.
Make breadcrumb parmesan topping by placing breadcrumbs, pine nuts, hemp seeds, and salt into a food processor and pulse until crumbly. Take half of the breadcrumb parmesan mixture and set aside for the topping.
Wash the head of cauliflower and slice it into thick slices, about ½ inch thick. Make sure to get out most of the thick stem.
Line the cauliflower pieces up on a tray and sprinkle with the other half of the breadcrumb parmesan mix, making sure to coat both sides of each piece. It doesn’t have to be fully coated, just looking for some added texture to the cauliflower. If your cauliflower is dry then you can always brush with veggie broth or oil to help get the mixture to stick.
Layer the slices into a square baking dish (I used 9 x 9 inches).
Pour the sauce over the top until it fully covers the cauliflower. You will use all but about ½ - ¾ cup of the sauce. You can save the extra for another time, it’s great with pasta!
Sprinkle the other half of the breadcrumb parmesan mix over the top. Then sprinkle with fresh thyme leaves.
Bake at 350°F/180°C for 35-40 minutes. Check at 35 minutes by piercing it with a fork to see how cooked the cauliflower is. I like it more on the al dente side, but you can continue to cook until your preferred texture is reached. Keep in mind it will cook a little more as it is cooling.
Make sure to allow the dish to cool before serving to allow it to set a bit. Enjoy!