Sour Cream Chocolate Cake (Grandma Spackman's)

3 oz semi sweet chocolate
1 c boiling water
1 1/4 tsp baking soda
Melt chocolate in boiling water, cool, add soda.

1/2 c butter
1 tsp vanilla
2 c berry sugar
3 eggs (separated)
2 1/2 c flour
1/2 tsp salt
1 c sour cream
Work butter, add vanilla and 1 1/2c sugar, cream together.
Add egg yolks. Sift flour and salt and add alternately with sour cream. Add chocolate.
Whip eggs whites to soft peak, add remaining sugar gradually. Beat to stiff peaks
Fold in.
Bake in 3 layers at 350 for 30-40 minutes