Prepare the soy shredded according to the instructions on the packet. In the meantime, cut the leek into strips and dice the onions.
Fry the onions in oil, add the soy slices. Add the leek with the tomato paste, the stock, the mustard and the spices to the soy shredded. Simmer for about 15 minutes, stirring frequently.
Finally stir in the soy cream. For a little more spiciness, I like to add some harissa.