My sister`s Delicate Plum Pudding

Ok, i have not tried this as of yet, because it calls for suet, in which I don`t know as in regards to cooking what suet is, as I am just an hillybilly and not up to snuff on those things. The only suet I know is what you put out for the birds in winter to feed them, you know the wild birds , such as red birds ( Cardinals). If anyone out can tell me what suet is please let me know. They must have known what suet was back in the year 1967 , as that is what year this recipe was put in the Kansan`s Silver Spoon Cookbook.

My Sister`s Delicate Plum Pudding
Mrs. Frances O`Toole

2 pints dry bread crumbs ( the inside of a stale loaf of bread)
1 pint suet, ground ( don`t press down) ( as I said don`t have any idea what this is)
1 pint light brown sugar
1 teaspoon soda
1 pint buttermilk
3 eggs, well beaten
1/4 teaspoon salt
1 cup seedless raisins
1/2 cup citron, chopped ( don`t know what this is either, as I said hillybilly)
3/4 cup pecans, chopped
1 1/2 teaspoon vanilla
1/2 teaspoon orange extract

Dissolve soda in buttermilk. Mix all ingredients well and pour pudding into baking powder tins, filling them 1/3 full. This recipe will fill 4 such cans. This recipe will require you to cover the tins with yellowed buttered paper. Tie with strings so pudding will not stick. Arrange paper above can so there will be room for pudding to rise. Now place in kettle of boiling water, without a lid. The water must come up 1/2 way on the tins. Let steam 2 hours. Remove from tins, slice in 1 1/2-inch slices and serve. Top with anything you wish.