Dark Fruit Christmas Cake from before 1950

Ingredients:

1 cup of butter
5 eggs
1 teaspoon baking soda
1 cup of strawberry jam
1 teaspoon lemon flavouring
2.5 cups flour
2 cups seedless raisins
2 cups seeded raisins
2 cups currants
1 cup chopped mixed peel
0.5 cup citron
1 cup glazed cherries (cut in half)
1 cup crushed walnuts
1 cup light brown sugar
0.5 cup sour milk
0.5 cup molasses
1 teaspoon vanilla flavouring
1 teaspoon each of nutmeg, cloves, cinnamon, allspice, and mace

Method: Cream (mix) butter and sugar until very light. Add the well beaten eggs. Dissolve soda in sour milk, and add to the creamed butter and sugar mixture. Add molasses, strawberry jam, flavourings, and spices to cake batter. Sift flour over fruit and peel, and mix together well. Add to cake batter and mix well. Pour into greased pan, cover with foil, and steam for 3 hours. Use a cake pan covered with foil, place in a large covered roaster with a small amount of water. Steam at 215C Remove from roaster and place cake in oven at 215C for 45 minutes to dry.