Position a rack in the center of the oven and preheat to 300ºF. In the bowl of a stand mixer fitted with the whip attachment, beat the egg whites, salt, and cream of tartar on medium-high speed until foamy, 1 minute. Increase the speed to medium high and gradually sprinkle in the sugar. Beat until the mixture is glossy and holds stiff peaks, 3-5 minutes. Turn the mixer to low and beat in the vanilla and almond extract just until combined. Remove the bowl from the mixer and sprinkle the almonds, poppy seeds, and almond extract over the meringue. Gently fold in until just combined.

Dab a little meringue on four corners on the underside of the parchment paper to glue it to the pan. Spread the meringue into scant ½ inch thick oval. Sprinkle with extra almonds and poppy seeds.

Place the meringue in the oven and bake for 20-30 minutes, or until the meringue is light golden. Lower the oven to 250ºF and bake until the meringue is firm to the touch, 30-45 minutes longer, watching the meringue closely and lowering the oven temperature further if it seems to be browning too much. Turn the oven off, prop the door open with a wooden spoon, and let the meringue cool to room temperature, 30-60 minutes. Break the meringue into large shards – it should taste slightly caramelized and be crisp and dry throughout. Store airtight at room temperature for up to 1 week until ready to use. If the meringue becomes soft, you can crisp it back up in a low oven.

In a large saucepan, stir together the sugar and cornstarch. Add the cherries and water and toss to combine. Place over medium heat and bring to a simmer, then reduce the heat to maintain a gentle simmer and cook, stirring frequently, until the juices have thickened to a sauce, 10-15 minutes. Chill the cherries until cold, 1-2 hours and up to 1-2 days.

Place the cream, yogurt, sugar, and vanilla in the bowl of a stand mixer fitted with the whip attachment. Whip on high until the cream holds soft peaks, being careful not to overwhip. (If you do take it too far and the cream starts to clump up, you can gently fold in fresh heavy cream to loosen up the mixture.) Use right away, or chill for up to 2 days.

To serve, divide the whipped yogurt cream among 4 shallow bowls. Spoon the cherry compote over the cream and swirl once or twice with the back of a small spoon. Tuck meringue shards beside the cream or crumble them over the top. Decorate the bowls with sweet cherries (halved and pitted if you like) and a few sliced almonds and poppy seeds. Serve right away.