Special equipment: a frying thermometer; a doughnut dropper
For the chocolate cake doughnuts: Combine the flour, sugar, cocoa powder, baking powder, baking soda and salt in the bowl of a stand mixer fitted with the paddle attachment. Mix on low until well-combined, 2 minutes.
In a medium bowl, whisk together molasses, vanilla and eggs with the 1/4 cup oil and 2 cups water. Pour the wet ingredients into the dry ingredients and mix until combined and smooth, about 1 minute.
In a large Dutch oven, bring 5 to 6 inches of the oil to 360 degrees F. Transfer the dough to a doughnut dropper and drop several doughnuts into the oil; cook 1 minute, then flip and cook the other side 1 minute more and transfer to a rack to cool. Repeat with the remaining dough, bringing the oil back to 360 degrees F before continuing to fry.
For the passion fruit glaze: Combine the confectioners' sugar, passion fruit pulp, agave nectar, palm oil, lemon juice and turmeric in the bowl of a stand mixer fitted with the paddle attachment. Blend on low until any lumps are dissolved. If the glaze is too runny, add more confectioners' sugar. If it's too thick, add more passion fruit pulp.
Dip the tops of the cooled doughnuts into the glaze, then transfer to a rack to set. When the glaze is set, drizzle the tops of the doughnuts with melted chocolate and dust with the sprinkles.