Looks kind of brainy. Cinnamon and butter brainy.

So much butter. So, so, so much butter.

Only after I followed the recipe in the book and the cake went in the oven did I look up this style of cake up on the internet. My typical way with a completely new recipe is to look at least 4,  compare them and go with the middle of the road or the recipe that tends toward the median. Well Anne Byrn's recipe calls for many more butters than the other recipes.

So in the quest to do things I've never done before, I've never riced a potato for a cake before. I have done it for gnocchi so this was fun. Also using warm potato water to foam the yeast was new. This is the 6th cake I've made from the American Cake. 

All this talk, there is also sugar, flour, cinnamon and eggs. You know, the yummy things found in cake. Oh and it take hours and three rises, so this is more of a weekend kind of cake, not an after work cake.

The recipe:
1 medium baking potato, peeled and diced
2.25 teaspoons yeast
.25 teaspoon sugar and 1 cup sugar
.25 cup of the reserved potato cooking water, plus 2 tablespoons
4 ounces shortening
2 ounces butter
1 teaspoon salt
2 eggs
3 cups flour plus plenty more for kneading
1 cup (2 sticks - a half pound -seriously)
1 cup brown sugar
2 teaspoons cinnamon

Put the potato on to boil. When it's tender, drain and reserve the water. Rice the potato or mash it, adding back 2 tablespoons of the reserved potato water. Keep this warm.
In a bowl combine the yeast, the .25 teaspoon sugar, the .25 cup potato water. Allow to foam about 5 minutes.
In a mixing bowl combine the riced potatoes, the yeast mixture, the cup sugar, shortening, the 2 ounces of butter and salt. Mix until the shortening is melted and there are no lumps.
Rise One. Cover and let rest 1.5 hours.
Add eggs, blend then add the flour. It will be sticky. Oil the bowl and the top of the dough. Let it sit covered with plastic wrap and a towel for 1.5 to 2 hours for Rise Two.
On a well floured surface, knead the dough for five minutes. Add additional flour to make this process manageable, however don't add too much. It should be moist. Press it into a greased 9x13 inch pan. Cover with plastic wrap and allow it to rise for 90 minutes, for Rise Three.
Preheat oven to 375 degrees.
Poke it down with your fingertips, be aggressive but don't flatten the dough. Dot liberally with the half pound of butter cut into very small pieces into the finger indentations. Combine the cup of brown sugar with cinnamon and sprinkle over the top of the cake.

Bake for 35-40 minutes, or until when you press in the center of the pan it has some resistance.