The best yellow senape mustard I ever tried is one I bought at a middle/far east shop almost 20 years back. It was different from others I knew for having a harder consistency, a bit harder than peanut butter to give an idea; I had to apply some force with a spoon in its big jar to cut a piece. Used it to give more flavor to meat by putting it in the frying pan along with oil and other spices, and the result was delicious. Unfortunately I don't recall the name, the shop changed owner although it still sells oriental spices, but now they have no idea of what product I'm talking about. Does anyone know if such a type of "hard" senape mustard still exist?