Begin by preheating your oven to 350°F (175C/155C Fan) and preparing your cake pans. If using traditional cake pans, grease and flour these. If using silicone, no preparation is needed.

In a large mixing bowl or the bowl of a stand mixer fitted with a paddle attachment, add the sugar and softened butter. Cream together on a low setting until light and fluffy (about 2 minutes).

Add the eggs one at a time, beating after each addition.

Then add the yoghurt, blueberry jam, lemon zest, and extracts. Beat lightly to combine in a smooth batter.

Sift the flour, baking soda, baking powder, and salt into the liquid mixture and beat or stir until smooth and just combined.

Pour evenly into prepared cake tins and smooth the tops.

Bake in the centre of the preheated oven for about 45 minutes, checking until a toothpick inserted in the centre comes out clean.

Once done, remove from the oven. Allow to cool in the cake pans for about five minutes before carefully turning out onto a wire rack to cool completely.

When ready to assemble, make the easy blueberry buttercream by mixing together the powdered sugar, melted butter, vanilla, and blueberry jam. Add a few tablespoons of milk and stir. Add more slowly as necessary until you reach your desired consistency.

For best presentation, level your cake layers by trimming any domed tops off as evenly as possible to create flat tops to the layers.

Using about ¼ of your frosting, spread a layer of blueberry buttercream over the top of your base cake layer. Then pipe a border around the outer edge of this about 1" thick.

Add about ¼ cup of blueberry jam inside this icing border and spread out. This will be your blueberry jam cake filling.

Invert your top layer so that the side you have trimmed and levelled is facing down. Sandwich this onto the blueberry jam.

Use your remaining blueberry buttercream to frost the top and sides of the cake and top off with the remaining blueberry jam.