Coffee and Walnut Streusel Cake with French Coffee Buttercream

This Coffee Sponge Cake has two delicious toppings, a crunchy walnut streusel and a coffee buttercream. The toppings join the two sponge layers and ice the top cake as well, so really that is four layers of toppings, bliss. Toppings like this should be mandatory for all coffee cakes. This was our very special Easter cake.

 

I have a guest baker for this cake post, my lovely and talented daughter, Shannon. She loves to bake and also owns a copy of  Emelia Jackson's book, " First, cream the butter and sugar", the original source of this recipe. Shannon happily took over my kitchen, adapted the recipe slightly, and this delicious cake was the result. We were smitten with this confection over Easter, pure baking bliss. 

Even if you aren't a coffee fan, and we have friends who only drink tea, so I understand, please don't be deterred by the fact that this is a coffee cake. The coffee flavour is very subtle, however it does seem to strengthen slightly with refrigeration over a few days. Three of us enjoying a slice a day, each day over Easter, and it just kept getting more delicious each day. I know you are doing the maths, and yes that is 12 slices. Admittedly, the last few slices were a wee bit smaller, but that was okay as the Easter Bunny had also visited by then.

I was first introduced to Coffee and Walnut cake by my Mum, also a passionate baker and I loved hers. She iced it with normal coffee icing, just icing sugar, softened butter and warm milk, not buttercream, and there was no streusel back then, but it was still delicious. After I left home and was married, she always made me her Coffee and Walnut cake cake whenever we were visiting her at home, and it was very special. 

I first posted the original recipe for Hope's (Mum's) Coffee and Walnut cake back in 2019, so here is the link to Mum's cake, if you would like it. It is a simpler version of this  Coffee and Walnut Streusel Cake, but still very much one of my favourites.

Coffee and walnut streusel really are the best of friends in a cake. 

Makes an 18 cm (7 inch) two-layer cake

Ingredients:

200 g (7 oz) unsalted butter, softened

125 g (4 1/2 oz) light brown sugar

100 g (3 1/2 oz) caster sugar (superfine)

4 eggs

2 teaspoons baking powder

1/2 teaspoon bicarbonate of soda (baking soda)

1/2 teaspoon salt

20 g (3/4 oz) instant coffee powder, dissolved in 2 tablespoons hot water

250 g (9 oz) plain (all-purpose) flour or cake flour

100 ml (3 1/2 fl oz) full-cream milk

75 g (2 1/4 oz) finely chopped very fresh walnuts

Streusel topping

50 g (1 3/4 oz) unsalted butter, softened

65 g (2 1/4 oz) plain (all-purpose flour)

40 g (1 1/2 oz) demerara sugar

30 g (1 oz) very fresh walnuts, roughly chopped

1/2 teaspoon ground cinnamon

Pinch of salt

Method:

Preheat your oven to 160 deg. C (320 deg. F)

Line two 18 cm (7 inch) round cake tins with baking paper.

Line a baking tray with baking paper or if you have them, silicone baking mats.

Making the streusel topping

Combine the butter, flour, and demerara sugar in a bowl and rub it all together with your fingertips, the old fashioned way. This will form into coarse crumbs. To this mixture add the salt, cinnamon, and walnuts, and toss through to combine. Spread this mixture over your lined baking tray and bake for 15-18 minutes or until golden brown. You now have your delicious crunchy streusel.

Set aside to cool.

The Sponge Cake

Fit the paddle attachment to your electric mixer.

Cream the butter and the sugar, until pale and very creamy. 

Now add the eggs, one at a time, and mix these in until they are fully incorporated into the mixture.

Don't worry if the mixture looks slightly curdled, it will be remedied when the dry ingredients are added.

Add the bicarbonate of soda, baking powder, coffee mixture and salt and mix them in to combine. 

Remove the bowl from your machine, and stir in the flour, milk, and walnuts until just combined. Make sure you scrape down the sides of the bowl, and mix any dry ingredients still in the base of your bowl.

Pour the batter evenly into your two cake tins and bake for 35-40 minutes. Test that they are cooked by inserting a skewer into the centre of the cakes. It will come out clean.

Leave the cakes to cool in the tin on a cooling rack for 10 minutes, and then remove the cakes from the tin onto the rack to cool completely.

French Coffee Buttercream (see Cook's notes below for quantity)

100 g (3 1/2 oz) egg yolks 

100 g (3 1/2 oz) caster (superfine) sugar 

1 tablespoon instant coffee powder

1 teaspoon vanilla bean paste

250 g (9 oz) unsalted butter, softened

Buttercream Method:

Combine the egg yolks, sugar, coffee powder and vanilla into a heat proof bowl. Shannon used one of my pyrex heat proof bowls to do this, however Emelia Jackson recommended using the heat proof bowl from her electric mixer, which I have never done. I think I would continue to use a pyrex bowl to do this, but my Kitchen Aid bowl is metal and is definitely heat proof as well. You make the choice as to what you are comfortable with.

Half fill a saucepan with water and bring it to the boil. Place the heat proof bowl in the saucepan, well above the boiling water, and cook, stirring constantly, until the sugar has dissolved. 

Fit the whisk attachment to your electric mixer. 

Secure the bowl to your electric mixer, and whisk until the egg yolk mixture is aerated and thickened. This will take about 6-8 minutes.

During this time the mixture will cool down, so by the end of the 8 minutes the bowl should be cooled down, before the butter is added, or it will melt, and we don't want that.  Of course, this will depend on the temperature of your kitchen.

So once the egg yolk mixture mixture has essentially cooled, add the butter to the bowl, and whisk again until it is creamy and Buttercream light in texture. 

Now if you want to take this cake to the next level for a special occasion and if you are adept with a piping bag, like Emelia Jackson is, the buttercream can be piped onto the cakes. Here's how:-

Transfer the buttercream to a piping bag which is fitted with a 1.5 cm (5/8 inch) star nozzle. 

Grab your serving plate, and place one of the cakes (the bottom layer) on it. Pipe buttercream rosettes around the outside of the cake only. Fill the hollow with some more of the buttercream and then sprinkle freely with the streusel topping. 

Add the second cake to the bottom one, now that you are an expert, pipe more rosettes of buttercream on the top to cover it and garnish with the remaining streusel.

Cook's notes:

• Shannon didn't use the piping bag to pipe rosettes onto the cake this time, so she only made half the quantity of buttercream and it was plenty for icing both layers of the cake. 
• The delicious layer of the streusel combined with half the buttercream was a perfect topping for the cake.
• We thought the mixture looked slightly curdled after it was mixed, before adding to the cake tins, so if that happens don't be concerned. The sponge cake still cooked beautifully and had the perfect crumb and was light and delicious.

A slice of  this cake, served with Flat White Coffees made for us by Mr. HRK at home, was the perfect indulgence over Easter. Note the Coffee Art on each coffee, he is quite the talented barista. He also roasts his own coffee beans always delivered from overseas, which we buy green from our online supplier. This batch of coffee beans came from the Shakisso Estate in Ethiopia. Delicious! 

If you have a special occasion just around the corner, this will be the perfect cake to celebrate with. Thanks so much Shannon for making our Easter even more special than it already was with this memorable cake.

 It's Anzac Day tomorrow, always the 25th of April in Australia, and a long weekend, when we remember the soldiers and family members of the Australian and New Zealand Army Corps, those who also fought during World War II, the Vietnamese War, and others who bravely went away to war to defend our freedom, and also those who are still serving in many capacities to protect our country. 

I'm not reposting my full Anzac Biscuit recipe again tomorrow, which I posted back in 2022, and which we bake every year to commemorate Anzac Day. Whilst I've been tempted to change different aspects of it, I keep going back to my original recipe, to ensure I bake a crispy and delicious biscuit. They must be crispy. 

This is the link to my Anzac Day recipe, and also some more back story to the poignant history of the Anzacs.

When the Last Post plays on the bugle during the Anzac Day Dawn Service and throughout Anzac Day, I always think of my wonderful Dad, Herb Davison, who died too young when I was only 9 years old, as a result of World War II injuries in New Guinea, and I shed a quiet tear. 

Lest We Forget!

Warm wishes

Pauline