Preheat the oven to 170℃, line an 8x8 inch tin with baking paper and lightly brush with butter/oil.
In a mixing bowl add the brown butter, brown sugar, white sugar and whisk until smooth and creamy.
Add the egg, vanilla and whisk again until thick and pale.
Add the flour, baking powder, baking soda, salt and fold together with a rubber spatula until combined.
Pour into the prepared tin and even it out with a spoon.
In the same mixing bowl let us make the almond cream but mixing the butter and sugar until combined.
Add the egg, vanilla, almond extract and whisk again until smooth.
Add the almond flour, corn flour, salt and whisk until smooth. Pour over the blondie layer in the tin.
Cut the croissants into cubes and top the almond cream with it, add the flaked almonds and castor sugar.
Bake for 18-22 minutes until golden and slightly puffed. If we press the top it should sink a littler without any raw batter oozing out.
Allow the bars to cool completely before dusting with icing sugar and cutting into bars. Serve with black coffee.