Here is the link to the Coffee and Walnut cake recipe I used.
It's a BBC website so it's reliable and SFW.
Shown below too.
I read through most of the comments and made amendments.
Ingredients
125g butter, at room temperature
125g caster sugar
2 eggs
125g self-raising flour
1 tsp baking powder
2 heaped tbsp coffee, dissolved in 100ml water
100g walnut halves
ICING
200g butter
2-300g icing sugar
1. Heat the oven to 170C/fan 150C/fan 3. Line a deep 18cm loose-based or springform cake tin. Beat the butter and sugar together with electric beaters and then beat in the eggs, flour and baking powder.
2. Beat in 1 tbsp of the coffee mixture and then add up to another tbsp little by little until the mixture drops easily off the spoon. Keep the rest of the coffee mixture for the icing.
3. Stir in half the walnuts, snapping them in half as you drop them into the bowl. Spoon into the tin, level the top and bake for 40 minutes or until a skewer comes out cleanly. Cool.
4. To make the icing, beat the butter until soft and then beat in 200g icing sugar followed by the remaining coffee mixture, little by little. Stop when you have a depth of colour and flavour that you like. If the icing looks a little soft, beat in extra icing sugar.
5. Cut the cake into 3 slices horizontally and then sandwich the layers together with some of the icing, you need a reasonably thick layer. Ice the top of the cake with the rest of the icing and decorate with the rest of the walnuts.
Amendments.
I upped the 125g butter, flour and sugar to 200g.
I then split into three 18cm pans, so that I could assemble more easily.
I smashed up the walnuts in the cake - they were there, but just not in big bites.
I kept the ones for decoration as halves of course.
I added the coffee to the cake as recommended, but added an extra teaspoon to the icing. I wanted a good coffee taste.
The cake was a little crumbly.
But easily held together with icing.
It's an impressive cake while still looking home-baked, so I didn't worry
too much about appearance.