In a medium-sized saucepan, combine the sugar, honey and butter over medium heat. Once simmering, cook for 3 to 4 minutes -- it'll get a bit darker in color. Whisk in the baking soda.
Remove from heat and set aside. Beat your eggs in a measuring cup you can pour out of or small bowl. Whisking the honey mixture vigorously in the pot the whole time, drizzle a thin stream (see the video) of the eggs into the honey mixture as you keep mixing. Continue until all of the eggs are thoroughly whisked in.
Stir in the salt and vanilla and 3 cups of the flour with a spoon (it's too thick for the whisk). Stir in the last of flour 1/4 cup at a time, just until it's thick enough to be able to be rolled out easily. My arm got so tired stirring this and I had to call in some backups. :)
Preheat oven to 350*.
Flour the counter and roll the dough out onto the flour, turning to flour both sides. Shape it into a disk and divide the still-warm dough into 8 even pieces. Roll the first one out to a bigger than 9" circle, keep making sure you've got enough flour on each side so it doesn't stick -- this is important so you don't lose your mind, FYI. Use the bottom of a 9" cake pan or something similar to cut out a 9" circle. (Save the trimmings, you're going to use those!)
Put the 9" circles and trimmings onto a parchment paper lined cookie sheet and poke all around them with a fork. Bake for 6 to 7 minutes until it feels firm to the touch. Slide onto a rack to cool.
Keep rolling and baking until all the cakes and extra pieces are done, I reused the parchment paper each time. Don't let the little pieces burn, they bake more quickly (check at 4-5 minutes), so you may want to bake them on a separate cookie sheet.
Let the cakes and pieces cool well while you make the filling/frosting...
Whisk sour cream and sweetened condensed milk together in a large bowl. Once cakes are cool, place a dab of the sour cream mixture on your cake plate and place the first cake on top of it to hold it in place.
Cut or tear one of your used sections of parchment paper into pieces and put them all around the underside of the cake -- this is so the cake plate is pretty when you're done. (Again, see the video for how to do this.)
Scoop 3/4 cup of the filling onto the center of the first cake layer. Spread it only a little from the center, leaving a 1- to 2-inch margin of unfrosted cake. Stack the second cake on top and repeat until you have 8 layers.
For the top layer, let it drip down the sides. This will look messy and slip around a bit, but it all turns out pretty!
The original recipe said to let this set overnight, but there was no way we weren't eating this cake SOON because it smelled so good!
So you can leave it overnight OR just pop into the fridge for an hour or two to let it set up some.
Throw about half of the extra cookie pieces into a food processor (or crush in a baggie using a rolling pin) to make into fine crumbs.
Take the cake out and straighten up the layers. If you’d like to make a decoration on top of your cake, take a piece of parchment paper and cut a stencil with it, I did a heart. Place it gently on top of the cake.
Sprinkle the top with the crumbs -- I didn't try to do the sides, but you can if you want.
Remove the stencil and parchment paper strips carefully. To slice, run a knife under hot water then dry it and use that so it goes through nicely.
If you still have some cake pieces left, dip them into any remaining filling -- yum!
Originally adapted and modified from this recipe
-- read more recipe notes there if you like extra details.