When measuring flour, we spoon it into a dry measuring cup and level off excess. (Scooping directly from the bag compacts the flour, resulting in dry baked goods.) Hachiya persimmons should be very ripe to provide you with the very sweet pulp that’s best for desserts like this one. They’re typically sold somewhat firmer than is ideal; if yours are on the firm side, place them in a brown paper bag, close the bag and let them ripen for 3 to 5 days.