Leave the croissants out for several hours to harden slightly.
To make the almond cream, mix together the butter and sugar then add in the extracts and the egg and mix well. Add in the flour and stir until combined.
Slice the croissants in half and spread some of the sweet almond paste onto each one then sit them onto a lined baking sheet.
Mix together the almonds, oats and blueberries and divide evenly between the croissants topping the sweet almond paste.
Place the oven for around ten minutes until warm, bubbling and golden.