Moravian Sugar Cake

Ingredients

• 1 medium russet potato, about 8 ounces
• 1 packet active dry yeast, about 2 1/4 teaspoons
• 1/4 cup warm potato cooking water
• 1/2 cup granulated sugar
• 8 tablespoons unsalted butter, softened
• 1/4 cup vegetable shortening
• 1 1/2 teaspoons salt
• 2 large eggs
• 1/2 cup warm whole milk
• 4 to 4 1/2 cups all-purpose flour
• 3/4 cup dark brown sugar, for the topping
• 6 tablespoons unsalted butter, cut into small cubes, for the topping
• 2 teaspoons ground cinnamon
• 2 tablespoons heavy cream

Before you cook

• Peel the potato, cut it into chunks, and boil it in salted water until tender, about 15 minutes.
• Reserve a quarter cup of the cooking water and drain the potato.
• Mash the potato smooth and measure one cup, then let it cool to warm.
• Cool the reserved cooking water to about 110 degrees Fahrenheit and stir the yeast into it.
• Butter a 9 by 13 inch baking pan.

Steps

1. Beat the warm mashed potato, granulated sugar, softened butter, shortening and salt in a mixer until the mixture looks loose and curdled.
2. Beat in the eggs one at a time.
3. Pour in the foamy yeast water and the warm milk and mix on low.
4. Add four cups of flour a cup at a time, mixing until a soft, sticky dough forms.
5. Add more flour only until the dough pulls from the sides of the bowl but still clings to the bottom.
6. Knead on medium speed for six minutes, until the dough is smooth and elastic.
7. Cover the bowl and let the dough rise in a warm place until doubled, about 90 minutes.
8. Punch the dough down and press it evenly into the buttered pan with buttered fingertips.
9. Cover the pan and let the dough rise again until puffy, about 45 minutes.
10. Heat the oven to 375 degrees Fahrenheit.
11. Push your fingertips deep into the dough all over, making wells about an inch apart.
12. Stir the brown sugar and cinnamon together, then spoon the mixture into and over the wells.
13. Drop the cubes of butter into the wells and drizzle the cream across the whole surface.
14. Bake for 25 to 30 minutes, until the topping is bubbling and the edges are deep brown.
15. Cool the cake for 15 minutes, then cut it into squares and serve it warm.