How to substitute for mustard seed<br>Use prepared horseradish to add spice. Prepared horseradish is made by combining ground horseradish with vinegar, and sometimes other spices, to form a sauce. You can get it from your local supermarket.
Prepared horseradish is an acceptable substitue for mustard seed.
( z1 replace :ARG1 ( z2 seed :mod ( z3 mustard ) ) :ARG2 ( z4 horseradish :ARG1-of ( z5 prepare ) ) :ARG1-of ( z6 accept :ARG1-of ( z7 possible ) ) )