To make cheese sauce: Add broth, butter and tapioca flour to a saucepan and cook over medium heat, until tapioca flour has dissolved. Continue stirring and bring the mixture to the boil and then remove from heat, it should be quite thick. Add in the yeast flakes, onion, garlic and sea salt. Whisk well, then add the almond meal. Bring back to the heat for 2 minutes.