First up; preheat your oven to 190°C/170°C/Gas Mark 5. Grease and line a 12”x 8” rectangle baking tin. Melt the butter in a pan over a low heat, once it starts to bubble remove from the heat and pop in the White Chocolate and sugars. Stir until the chocolate has melted, if needed place the pan back over a very low heat and stir until the chocolate has melted. – if the mixture looks like it is beginning to separate don’t worry it’ll come back together once you add the eggs.

Pour the chocolate mixture into a bowl and leave to cool for 5 minutes. Add the eggs and Vanilla Extract and whisk the mixture on a high speed for 2-3 minutes – this will help create the smooth shiny top on your blondie. It is easiest to do this step using a hand whisk or freestanding mixer with the whisk attachment.  

Fold in the flour and custard powder until just combined. Break the biscuits into pieces and mix through the blondie mixture with the White Chunks. 

Pour the mixture into the prepared baking tin and smooth the top. Pop in the oven and bake for 35-40 minutes until golden brown on top, the edge of the blondie should be set and the centre slightly wobbly, this will firm up as the blondie cools.

Leave to cool in the tin, once cool you are ready to decorate! First up, pop the butter into a large bowl or free-standing mixer and beat with an electric whisk until softened and smooth. Add the icing sugar in 3 intervals ensuring it’s mixed after each addition. Pour in the Vanilla Extract and beat until light and smooth. 

Divide your buttercream equally between 3 bowls and add Red Colour Gel to one bowl and Blue Colour Gel to another and mix until you have a bright red, blue and white buttercream. Pop each colour into separate piping bags fitted with a small open star nozzle – if you do not have 3 of the same nozzles you can cut a small hole in the end of each piping bag and pipe dots of buttercream or use 3 different nozzles with a similar size opening.

Cut your tray of blondie in half lengthways and then cut into triangles, you need to make sure your blondie is properly cool before cutting. Lay your blondie triangles on a lined tray and pipe your buttercream on top. We did diagonal stripes, random dots and whole colours but you can get creative and make any designs you like! Once you have finished decorating your blondie bunting you can display ready to serve to your guests!