From the Cambrian Daily Leader, 29th December 1914.
[What sort of Yorkshire pudding was seasonal, and obtained from grocers? None that I have heard of.]
[Many ads were beginning to refer to the war - especially ads for products that the people at home could send to their men at the front. Oxo was a meat extract, sold in a jar (like Bovril) or in cubes. I think "Oxo is made in a moment" refers to making a hot drink from it. The beef stock cube is still the main product sold under the Oxo brand, but it has diversified into other products as well.]