Here's one Ellie, I haven't tried it but it sounds good. Hope it's what you
want.

MORAVIAN SUGAR CAKE
(Or Coffee Cake)

1/2 lb. potatoes, peeled
1 pkg. active dry yeast
1/4 c. warm water
3/4 c. butter and lard or
shortening, mixed
1 scant c. sugar (about 1
Tbsp. less)
2 eggs
1 c. potato water, warm
2 tsp. salt
5 to 7 c. all-purpose flour,
sifted before measuring
2 Tbsp. butter, cut up
1 c. packed dark brown sugar
1 tsp. cinnamon
1/2 c. light cream

Cook potatoes in water to cover until tender; drain,
reserving 1 cup of the water. Mash potatoes and measure out 1
cup. Add yeast to the 1/4 cup warm water and stir to dissolve.
Cream 3/4 cup butter mixture and sugar together well; beat in
eggs, one at a time. Mix in mashed potatoes, potato water,
salt and yeast. Gradually add flour, mixing in enough to make
a soft, sticky dough. Cover bowl with a damp towel; let rise
in a warm place (85 degrees) until double in bulk, 2 to 3 hours.
Punch down; pat into 2 well greased 13 x 9 x 2-inch pans.
Cover with damp towel and let rise until double, about 1 1/2
hours. Heat oven to 400 degrees. With sharp knife punch small holes
in top of dough; insert bits of butter. Sprinkle with brown
sugar and cinnamon. Dribble cream over top; bake 20 to 25
minutes or until brown. Cake reheats very satisfactorily.
Makes 2 coffee cakes.