Pre-heat oven to 180°C / 160°C fan / gas 4 and grease a baking dish 27 x 17cm.
Coat the raspberries in 20g tapioca flour, reserving the other 50g for later.
Drop the raspberries into the bottom of the dish
Beat the butter and sugar together until light and fluffy. About 6 minutes in a stand mixer, scraping the sides down occasionally.
Add the eggs one at a time, beating well after each addition and then add the vanilla extract.
Whisk together the ground almonds, the rest of the tapioca flour baking powder and salt.
Add the flour mixture to other ingredients and beat well.
Pour the batter over the raspberries.
Bake for 50 minutes until the surface is golden.
Remove from the oven.
Rest the pudding for at least 15 minutes and sieve the icing sugar over the top just before serving.