Preheat the oven to 180'C / Fan 160'C / Gas Mark 4. Line a 9-inch (23cm) square baking tin with baking paper and set to one side.

In a large mixing bowl add the melted butter, caster sugar, light brown sugar and almond extract. Beat with an electric mixer (or wooden spoon) until combined.

Add the eggs to the mixture and beat again with the mixer until it starts to thicken. It should go slightly paler and fluffier - after around a minute or so of whisking.

Add the gluten free flour, xanthan gum and ground almonds and beat again briefly until combined with no lumps of flour. Fold in the chocolate chips.

Pour the batter into the lined baking tin and spread out into an even layer using a spatula. Dollop the jam onto the batter and then use a knife to lightly swirl into the mixture. Sprinkles with the flaked almonds and then bake for around 20-25 minutes until the blondie is golden on top. It should still wobble slightly in the centre.

Remove the blondie from the oven and allow to cool completely in the tin before slicing up into squares.