Cake- Cream butter, sugar, and egg yolks. Stir soda into buttermilk and add to creamed mixture. Sift flour with spices and add a little at a time beating after each addition. Add the blackberries. Beat egg whites until stiffly beaten and fold into to mixture. Bake in 2 - 10 inch cake pans in 325 degree oven about 30 minutes or until toothpick inserted comes out clean.
Caramel Frosting- Melt butter in saucepan and add brown sugar boil over low heat 2 minutes stirring all the time. Add milk and keep stirring until mixture boiles. Remove from heat and cool. Add sifted powdered sugar. Beat well after each addition. Add pecans if desired.