Set a small sauce pan over medium heat. Add the sesame seeds to the dry pan and toast for 3-5 minutes. Stir and move around the sesame seeds in the pan frequently as they can easily burn. After the sesame seeds have a golden brown color, pour them into the bowl of a mini food processor or small blender.
Set the sauce pan back over low heat and add the heavy cream. Slowly, let the cream warm over but don't let it bubble.
While the cream warms on the stove, mix the rest of the sauce in your blender or food processor. To the sesame seeds, add the soy sauce, mustard powder, garlic powder, and water. Blend the mixture until it is completely smooth.
Combine the soy sauce mixture with the warmed cream and transfer to a serving dish.