Preheat the oven to 330F (165C). Line with parchment paper and grease the sides of a 9-inch (23-cm) spring form pan.
In a large mixing bowl, beat the softened butter on high speed for 2 to 3 minutes, until light and fluffy. Add the plain yogurt, honey and egg yolks next. Mix again for a few minutes until the batter is smooth. In a separate mixing bowl, combine the dry ingredients: flour, almond flour, salt and baking powder. Sift the dry ingredients into the batter and then fold gently.
In a separate bowl, whisk the egg whites on high speed for 3 to 4 minutes, until stiff peaks form. Add the egg whites to the batter. Roughly chop the pitted cherries, then toss together with the cornstarch in a large bowl until the cherries are well coated; add to the batter. Fold the cherries and egg whites gently into the batter, keeping the egg whites as fluffy as possible.
Transfer the batter into the prepared spring form pan and spread evenly with an off-set spatula. Bake in preheated oven for 1 hour 15-20 minutes, or until a toothpick inserted into the center comes out clean. Allow the cake to cool completely on a wire rack. Once cooled, use a wooden skewer to poke holes on the top.
Prepare the syrup: simply combine the 1/4 cup kirsch liqueur and 1 tbsp honey. Use a pastry brush to soak the cake layer with prepared syrup.
Prepare the whipped cream: in a large mixing bowl, whisk together the chilled heavy cream, kirsch liqueur and sugar until stiff peaks form. Transfer the whipped cream onto the cooled cake, sprinkle with slivered almonds and garnish with fresh cherries.
If not serving right away, I recommend keeping the whipped cream separate in the refrigerator; keep the cake wrapped tightly in plastic wrap at room temperature. When ready to serve, top with the whipped cream.