Preheat your oven to 450°. Place the prepared pizza crust on a pizza pan or pizza stone.
Place the sweet potato pieces in a medium-sized pot with enough water to cover them plus two inches. Boil over medium-high heat until the sweet potato is fork tender, about 10 minutes. Drain the sweet potatoes and allow them to cool for a few minutes.
While the sweet potato is cooling, place the kale pieces in a bowl and drizzle on the lemon juice and olive oil. Sprinkle with half a teaspoon of sea salt. Massage the kale until it begins to wilt.
Add the sweet potato to a food processor or high-speed blender along with 2 tablespoons of the non-dairy milk, ½ teaspoon of salt, the garlic powder, and ½ teaspoon of red pepper flakes. Process until smooth. If it’s too thick, add another tablespoon of non-dairy milk.
Spread the sweet potato puree on the pizza crust, leaving about 2 inches of bare dough around the rim. Dollop the cashew ricotta on top of the sweet potato, and then top with the massaged kale. Sprinkle the lemon zest on top of the kale.
Cook for 12-15 minutes, until the crust is golden and the ingredients are cooked throughout.
Slice and sprinkle with vegan parmesan and extra red pepper flakes, if using. Serve hot.