I found this recipe, which I'd forgotten, when I was sorting out my handwritten recipe book. My grandmother's cleaning lady gave it to her probably in the early 1960s - at least I can remember it being around for that long.
I've adapted it to an "all-in-one" recipe and it works well and is quick to mix. In theory it shouldn't work as most chocolate cake recipes say that Drinking Chocolate powder is unsuitable as a substitute for cocoa powder but this works every time. It might look a bit odd compared with American cake recipes but if you need a cake in a hurry it takes the prize.
Thought you might like it.
Grease and base line a 7" cake tin/pan. Set oven to 325deg F/180deg C/gas mark 4.
Put all the following into a bowl and beat until light and fluffy.
-4 oz self-r(a)ising flour sifted with 1/2 a teaspoon baking powder
-4 ounces softened butter (I use Lurpak Spreadable but you could use soft margarine if you absolutely had to.)
-5 oz soft brown sugar (I use part soft dark brown sugar and part soft light brown sugar but you can please yourselves).
-2 tablespoons (ie 2 x 15gr spoons) Cadbury's Drinking Chocolate powder mixed with 1and1/2 tablespoons cold water
-1 tablespoon boiling water.
Beat all together with an electric handmixer (or wooden spoon if you're annoyed with anyone
) until light and fluffy. Transfer to prepared tin/pan and bake in oven at the above heat for 3/4 of an hour.
Allow to cool them spread the top with good quality milk chocolate.
My Grandmother used to split the cold cake and sandwich it with raspberry jam but I think this over-gilds the lily.
When I've needed something a bit more special I've added grated orange peel to the mixture, baked two and sandwiched them with orange marmalade.
Cream is good but not essential as an accompaniment.
PS Cadburys is now owned by Kraft so Cadbury's Drinking Choc powder should be available in the US (try Amazon.com if any probs).