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 ¾ of the jammie dodgers into pieces and mix through the blondie mixture. 

Pour the mixture into the prepared baking tin and smooth the top. Dollop the jam over the top of the blondie and swirl through a little with a cocktail stick or knife, try not to swirl in too much as the jam will sink to the bottom of the blondie as it bakes. Scatter over the remaining jammie dogers, breaking some up into pieces and pop in the oven and bake for 40--45 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 serve and enjoy your wonderful jammie dodger blondie!