Moravian Sugar Coffee Cake - cooking recipe

Ingredients

1 pound potatoes, peeled and chopped
2 cups water
1/2 teaspoon salt
1/2 cup white sugar
1/2 teaspoon ground mace
1/2 cup butter, room temperature
1 egg, room temperature
3 1/4 cups all-purpose flour
2 1/4 teaspoons active dry yeast
1 cup dark brown sugar
1 tablespoon ground cinnamon, or to taste
1/2 cup chilled butter, diced
2 tablespoons chilled butter, diced
1 teaspoon evaporated milk

Preparation

Place potatoes and water in a medium saucepan. Bring to a boil. Boil until the potatoes are tender. Drain, reserving 1/2 cup water, and mash. Let cool to room temperature.
Place mashed potatoes, reserved water, salt, sugar, mace, 1/2 cup butter, egg, flour and yeast in the pan of a bread machine in the order recommended by the manufacturer. Select dough cycle; press Start.
Pat dough onto a greased 11x13 inch baking sheet. Cover with a damp cloth and let rise in a warm place until doubled in volume, about 1 hour.
Preheat oven to 350 degrees F (175 degrees C). Combine the dark brown sugar, cinnamon, and chilled butter in a food processor and pulse until butter is the size of coarse crumbs.
Poke several medium holes in the dough and fill with brown sugar and butter. Sprinkle the dough with a few drops of evaporated milk.
Bake in the preheated oven until the cake's edges are golden brown, 20 to 25 minutes.