In a deep sauce pan, mix the honey, sugar, and eggs. And the cubed butter and place the pan over low heat until it begins to simmer. Once it starts simmering, remove the pan from the stove and stir in the baking soda. Continue mixing until the mixture doubles in volume. Allow it to cool until it reaches a temperature of 35-40°C (95-104°F).

Once the mixture has cooled, gradually add the flour. Begin mixing the flour directly in the pan, then transfer the dough to a work surface. Continue mixing with a dough spatula until all the flour is incorporated. At this stage, the dough will be slightly warm and sticky to the touch, which is the desired consistency.

Transfer the dough to plastic wrap, shape it into a rectangle, and refrigerate for 30-40 minutes until it cools and hardens. To speed up the process, you can place the dough in the freezer for about 20 minutes.

While the dough is cooling, prepare the blackcurrant filling. In a small saucepan, cook the blackcurrants and sugar over medium heat, stirring occasionally, until the blackcurrants soften and release their juice. Use an immersion blender to blend the mixture until smooth. In a separate bowl, mix the starch with water to create a slurry, then add it to the blackcurrant mixture. Stir until the mixture thickens, then remove from heat and let it cool completely. Once cooled, transfer it to a piping bag and set aside.

Preheat your oven to 350°F (175°C). Cut two pieces of parchment paper.

Once the dough has cooled, cut it into 12 equal portions, approximately 70g each, and form into 12 balls. At this point, the dough should be easy to handle and no longer sticky.

Take one ball of dough and place it on one sheet of parchment paper. Dust the dough with flour and roll it out to slightly over 8 inches (20 cm) in diameter. Pierce the dough with a fork, then bake for approximately 3 minutes or until golden brown. While the first layer bakes, prepare the second one using the second sheet of parchment paper.

Once the first layer is done and still hot, use an 8-inch (20 cm) cake ring to cut the dough into a perfect circle. Place it on a cooling rack to cool completely. Continue rolling out and baking the remaining dough balls, using the same parchment paper. Set aside any leftover dough for decorating the cake.

After all 12 layers are baked and cooled, prepare the cream. In a mixing bowl, combine the sour cream, whipping cream, vanilla, and powdered sugar. Mix until the cream is fluffy and firm.

Place the first baked dough layer on a serving plate. Spread a layer of the cream mixture over it, using about two spoonfuls of cream for each layer. If necessary, add an additional half spoon to fully cover the dough. You should have enough cream to cover all 12 layers, as well as the top and sides of the cake. After covering with cream the second layer, add the blackcurrant filling over in a spiral pattern (do not spread it), then add the third layer of dough on top. Use the blackcurrant filling on every second layer. 

Repeat the process until all layers are assembled, finishing with a generous layer of cream on top.

Using a food processor, finely grind the leftover dough and sprinkle the crumbs over the top and sides of the cake.

Refrigerate the assembled cake for at least 4 hours, or preferably overnight, to allow the flavors to meld and the cake to set. Slice and serve chilled.