Preheat oven to 375 degrees. Grease an 8-inch cake pan or springform pan. Set aside.
Place dried cherries in a small sauce pan with apple juice. Stir to combine. Set over medium heat until simmering. Turn off heat and let sit for 30 minutes. In the meantime, make the almond cream (recipe below). Cover and refrigerate until needed. Once the cherries are done, drain out the excess juice.
Roll out the thawed pastry into a 16x10 rectangle. Slice into 4 strips (4inches x 10 inches each). Using on strip at a time, spread ¼ cup of almond cream into an even layer over the pastry. Lay ¼ cup of cherries along the bottom long edge of the pastry. Starting at the edge with the cherries, roll the pastry into a log. Repeat with 3 other pastry rectangles.
Starting at one edge of the pastry log, tuck into a pinwheel/spiral, making sure not to spiral too tightly. Place pinwheel in the center of the prepared 8-inch pan. Grab another pastry log and continue the spiral using the next log of pastry. Repeat with last 2 rectangles of pastry to finish off the cake.
Whisk an egg with 1 teaspoon of water. Brush mixture over the top. Sprinkle with coarse sugar. Bake in preheated oven until the pastry turns a deep golden brown on top, about 30 minutes. Remove from oven and let cool for 10 minutes. Remove from pan and place on serving plate.
Prepare the icing by mixing powdered sugar and heavy cream together. Add a little more cream if needed, to ensure the mixture can be drizzled. Drizzle over the cake and sprinkle with toasted sliced almonds. Slice and serve.