Hello, Elle! Here is the recipe you asked for taken directly from the Watkins Cook Book, published in 1936 by The J.R. Watkins Company:

Watkins Plain Butter Cake

1/3 cup shortening (butter)
1 cup sugar
2 eggs
1 cup milk
2 cups flour
3 teaspoons Watkins Baking Powder
1/2 teaspoon salt
1 teaspoon Watkins Vanilla

Cream shortening, add sugar gradually, blend thoroughly.

Beat eggs well, add to first mixture.

Mix, sift flour, salt and Watkins Baking Powder, combine alternately with milk. Lastly, add Watkins Vanilla.

Bake in buttered pan 35 to 40 minutes.