Heat the oven to 180°C. For the dough, mix flour and sugar in a bowl. Heat the 100 grams of milk to lukewarm and dissolve the yeast in it. Let stand for a while until it starts to bubble. Then add to the flour along with the coconut oil and mix into a smooth dough. Let rise for 30 minutes, covered, in a warm place.
Meanwhile, make the rice pudding by putting the rice with sugar, milk and vanilla extract in a saucepan. Add the cardamom, star anise and cinnamon. Bring to a boil and cook, stirring constantly. Take out the spices. In a small bowl, mix baking soda with lemon juice/apple vinegar. Stir well until baking soda is dissolved, then mix into the rice pudding.
Roll out the dough on a floured work surface (it is very sticky, but don't stress it will be fine) and line the bottom and edges of a greased mold with it. Spread the rice pudding over the bottom and bake for about 25 to 30 minutes.