Rhubarb Lemon Mousse Semi-naked Cake

‘The beginning of summer brings out the most prettiest of cakes’

It almost seems to have become a tradition that during this time, I tend to make a semi-naked cake for my birthday. I would honestly say, I’m starting to get the hang of them as I’ve played around with so many flavours these past years. Since it is rhubarb season, I opted for a lemon mousse rhubarb filling with a classic butter frosting on top. I used to rose buds, black berries and mint leaves for garnishing to keep it pretty and on theme. All the ladies loved the flavour combination as it’s lemony fresh but with density and sweetness from the rhubarb jam and frosting. For anyone who seems insecure about making a layer cake, it really is not that difficult and it can be made a day in advance which makes your life much easier on the day of the event. Semi-naked cakes is a beautiful cake to learn how to cake as it really makes a statement every single time.

We will begin by making the lemon mousse, frosting, layers for the cake and the rhubarb was ready from jar. If you are looking for more cake inspiration, see my other semi-naked cakes from here: summer cake & white chocolate raspberry

Let’s make a cake

Start by making the lemon curd (unless it is store bought) and then the layers for the cake. Make the butter frosting last. Depending on when you are going to assemble the cake, make the butter frosting during that moment.

Frosting Ingredients

  • 500g sifted icing sugar
  • 250g butter
  • 1-2 tablespoons boiling water

To make the butter cream, beat together butter (room temperature) and icing sugar on low speed with a hand held mixer. Add a few drops of boiling water to loosen the butter so it forms a lovely frosting as you mix.

Ingredients for Lemon Mousse

  • 1/2 cup lemon curd
  • 1 cup cold heavy whipping cream
  • 1/4 cup powdered sugar

For the lemon mousse, you basically mix 3 ingredients together; lemon curd, whipped cream and powdered sugar. You could store by the curd, but if you wish to make it yourself, the recipe is here. When making a layer cake, I tend to make the curd the day before along with the layers to save some time.

To make the Mousse: In a bowl, whisk the whipped cream and powdered sugar. Whisk in the lemon curd for about 3 minutes until soft peaks start to form. Place into a clean bowl, cover with clingfilm and refrigerate overnight.

Ingredients for cake base (x3)

  • 3 eggs
  • 1dl sugar
  • 1/2 teaspoon baking powder
  • 1 dl + 1 1/2 tbs flour
  • 1 tablespoons vanilla powder
  • ½ tablespoon lemon zest

* oil for lining the cake tine / milk when assembling the cake

Cake Base Directions (cake tin 16cm Ø )

Baking the cake layers:

In a bowl, add together the dry ingredients (minus sugar & lemon zest). In another bowl, whisk together the eggs and sugar until light and fluffy with the help of an electric whisk. Through a sieve, combine the dry ingredients to the egg/sugar mixture. Gently fold the batter together and add the lemon zest.

Pour some oil into the cake tin so the bottom and sides are coated, pour excess out. Pour batter into the cake tin and place into the bottom part of the oven for 40 minutes at 175 °C. Check the cake by inserting a tooth pick into the centre and if it comes out clear, it is fully cooked. Cool in cake tins on a heat rack (about 10 minutes); remove cakes from tins and cool completely on wire racks for about an hour.

Repeat this process once more for another layer

Freeze Cake layers:

Freeze cakes once cooled, as this process makes the assembling much easier. Wrap each cake layer individually in plastic wrap and freeze for 4-6 hours. This part is optional but it ensures that crumbs don’t break into the icing, so if you are short in time, freeze at least for an hour. If you freeze them overnight, give them a bit of time to defrost as they are hard to cut otherwise.

When you are ready to assemble the cake, remove layers from freezer and unwrap. Level the layers with a serrated knife to make sure the surfaces are straight. I removed the top half of the cake layers as they were dome-shaped. I also cut one of the layers in half, to get an extra layer for the center of the cake.

Assemble the cake

At this point, remove the lemon mousse from the fridge and have your rhubarb jam and butter frosting ready. I used an organic jam from the store but it’s great to do it yourself too, but I was feeling a bit lazy.

Use your “ugliest cake bottom” for the base of the naked-cake. Save the prettiest bottom for the top part. Place a bit of frosting on your cake plate and place the first layer on top. This keeps it from moving. Moisten each layer with a bit of milk.

Fill each layer with rhubarb jam and lemon mousse. Repeat this process until the top and place the last layer “with the bottom half of the layer facing the surface” so it looks flat this way. Add buttercream frosting around the edges of the cake and push it in the middle to fill any gaps and scrape to almost bare with a sharp knife. Place into fridge to set the frosting before decorating.

Decorate with black berries, mint leaves and dried rose buds, that you would use for tea.

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