Preheat the oven to 160C/320F (fan) and line a 20cmx20cm baking tin with baking parchment.
Melt one third of the white chocolate. You can do this in the microwave in 30-second bursts (stirring each time) or in a bowl over some simmering water. Put to one side.
150 g (5.3 oz) good quality white chocolate
Chop the remaining white chocolate into small chunks and put to one side.
Place the butter and sugar in a large mixing bowl and beat together using a wooden spoon until pale and creamy.
125 g (1/2 cup + 1 tbsp) unsalted butter, 200 g (1 cup) golden caster sugar
Add in the almonds, baking powder, coconut flour, eggs, vanilla, and milk. Stir until just combined.
150 g (2 cups minus 2 tsp) ground almonds/almond meal, 1/2 tsp gluten free baking powder, 50 g (1/3 cup + 1 tsp) coconut flour, 2 large eggs, 1 tsp vanilla extract, 2 tbsp milk
Stir in the pistachios, the melted chocolate and the chopped chocolate and then spoon out the mixture into the prepared baking tin (it should be a thick mixture). Push the mixture to the corners and smooth it with the back of a spoon.
60 g (1/2 cup) chopped pistachios
Place in the oven and cook for 40-50 minutes - until an inserted skewer comes out clean. NOTE: The top goes dark quite quickly, so it's a good idea to cover it with some foil after about 15 minutes in the oven.
Once cooked, take out of the oven and allow to cool completely in the tin.
Take out of the tin and remove the baking parchment. Melt the white chocolate for the topping and drizzle over the top, then sprinkle on the chopped pistachios.
50 g (1.7 oz) white chocolate, 2 tbsp chopped pistachios
Allow the chocolate to firm up a little, then cut the blondies into 16 pieces and serve.
Notes
These blondies will keep for 2-3 days in a sealed container at room temperature..Nutritional Information is per blondie.