Preheat the oven to 200°C/390ºF.

In a bowl or food processor, combine the almond and oat flour, tapioca starch, salt, coconut sugar, and 1 tsp vanilla extract.

Cut the cold butter into small pieces and add to the bowl. Using your hands, crumble the flour and butter together, or blitz in the food processor until the dough comes together. If the dough doesn’t come together and seems a little bit dry, add some more cold butter.

Grease your tart pan with coconut oil or vegan butter. Add the crumb dough into the pan and press down with either your hands or the bottom of a glass or mug, until the crumb is evenly spread. Make sure to press the edges of the pastry up against the tart pan, for a crumb rim.

Place the pan on a baking tray and bake for 20 minutes for a parbaked crust. Add desired fillings after this point and either allow the filling to set in the fridge (if making a dessert tart filling), or continue baking if doing something savory and warm like a quiche.