Heat the oven to 325°F with a rack in the lower-middle position. In a large Dutch oven over medium, combine the oil, half of the onions and ½ teaspoon each salt and pepper. Cook, stirring occasionally, until the onions are wilted and translucent, 7 to 9 minutes. Add the beef, ginger, turmeric, 1½ teaspoons salt and ½ teaspoon pepper; cook, stirring occasionally, until the mixture is fragrant, about 2 minutes.

Stir in half of the prunes, then nestle the garlic and cinnamon stick into the mixture. Distribute the remaining onions in an even layer over the top and sprinkle with ⅛ teaspoon each salt and pepper; do not stir. Add 2½ cups water, cover and bring to a simmer. Cover, transfer to the oven and cook for 2 hours.

Remove the pot from the oven. Carefully tilt the pot to pool the liquid to one side, then measure ½ cup of the braising liquid into a small saucepan. Return the pot, uncovered, to the oven and cook until a skewer inserted into the beef meets no resistance and the onions on the surface are lightly browned, about 30 minutes.

Meanwhile, to the saucepan, add the remaining prunes, the apricots, honey, cinnamon, ½ teaspoon each salt and pepper and ½ cup water. Bring to simmer over medium-high, then reduce to medium-low and cook, uncovered and stirring occasionally, until the fruits are plump and tender and have absorbed most of the liquid, about 15 minutes. Remove from the heat and stir in the sesame seeds; set aside.

When the beef is done, remove the pot from the oven. Using tongs, squeeze the garlic cloves from the head into the stew; mash the cloves against the side of the pot and stir them into the cooking liquid. Remove and discard the cinnamon stick. Taste and season the tagine with salt and pepper. Serve sprinkled with the parsley and almonds, and with the apricot-prune mixture alongside.