Place the sugar, honey, and unsalted butter in a medium saucepan. Set it over medium-low heat and warm gently, whisking from time to time, until the sugar has completely dissolved, about 5 to 7 minutes. Keep the heat gentle, as the sugar can easily scorch if the pan becomes too hot.

Once the sugar has melted, take the saucepan off the heat. While the mixture is still hot, slowly pour in the beaten eggs in a thin, steady stream, whisking constantly and vigorously. Take your time with this step so the eggs blend smoothly rather than cooking in the hot mixture.

Whisk in the baking soda until the mixture is completely smooth and free of lumps. Add the flour gradually, about ½ cup at a time, folding it in with a spatula. Continue until you have a soft dough with a clay-like consistency that no longer clings to your hands. The full 3 cups of flour should be enough when measured carefully, with the excess flour scraped level from the top of each cup.

Divide the dough into 8 equal portions. Begin rolling them right away while the dough is still warm, as warm dough is much easier to work with.

Lightly flour your work surface and roll each portion into a very thin 9-inch circle, approximately 1/8 inch thick. If the dough begins sticking to the rolling pin, dust the surface lightly with a little more flour.

Place a 9-inch plate or the base of a springform pan over the rolled dough and carefully cut around it with a pizza cutter to create an even circle. Keep all the leftover dough pieces, as they will be used later for the cake crumbs.

Move each circle onto a large piece of parchment paper. Bake two layers at a time at 350°F for approximately 4 to 5 minutes, or until they turn a lovely golden color. Transfer the baked layers to a wire rack and allow them to cool completely before stacking them. Continue until all 8 layers are baked.

Spread the reserved dough scraps evenly over a reused sheet of parchment paper and bake them as well. Once they are completely baked, cooled, and firm, crush them with a rolling pin or pulse them in a food processor until you have fine crumbs.

Pour the heavy cream into a bowl and whip it on high speed for about 1 to 2 minutes, until it becomes light, fluffy, and forms stiff peaks.

In another bowl, whisk together the sour cream and powdered sugar until smooth. Gently fold the whipped cream into the sour cream mixture until the frosting is evenly combined.

Place the frosting in the fridge until you are ready to assemble the cake.

Place the first cake layer on your serving surface and spread approximately 1/3 cup of frosting over it. The frosting will be fairly loose, but be generous with it. These thin layers need plenty of cream to soak in, which is what gives the finished cake its wonderfully soft texture.

Continue layering the cake and frosting, gently pressing each layer down as you work. This helps remove any large air pockets between the layers. Once all the layers are stacked, use the remaining frosting to cover the top and sides of the cake.

Finish by sprinkling the fine cake crumbs over the entire top and sides. Cover the cake with plastic wrap and place it in the fridge overnight.

Do not be tempted to rush this final step. The cake needs several hours to absorb the creamy frosting and soften properly. By the next day, those crisp layers will have transformed into a wonderfully tender, delicate cake.

As one batch of layers is baking, continue rolling out the next ones. This keeps the process moving and means the total baking time for all the layers should be around 25 minutes.

If a few layers puff up or form bubbles while baking, do not worry. The frosting will cover them beautifully. If you notice a particularly large bubble, gently press it down after removing the layer from the oven.

You can reuse the parchment paper between batches, which is a simple way to save a little waste.

If your baking sheet is not large enough to hold the parchment paper, you can place the parchment directly on the oven rack and bake the layers that way.