The second point: the oil cake itself is not a flour cake, but it is made of dead dough, but I personally suggest that you can add a small amount of baking powder when kneading the dough, so that the baked oil cake will have a certain sense of bulkiness and the crust will be crisp.
The third point: When the kneaded dough is relaxed, you can brush a layer of cooking oil on its surface, which is to lock the moisture and make the dough more malleable, which is convenient for subsequent molding operations.
As long as you master the above three kneading skills, the cake is crisp outside and soft inside, even if it is cold, it is not hard, which is worth learning.