Here is my favorite:
Light mayo
Stone ground mustard
Thai fish sauce (or soy sauce if you aren't brave enough after smelling it)
Black pepper
Lemon juice
Dill

Mix all the wet ingredients - but remember the mayo just holds all the other ingredients together so don't use too much. Then throw in the dry ingredients and spread on top of a filet. The exact ratio doesnt really matter - its hard to screw this one up. I like to BBQ it on a foil boat until the top is just brown.
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One does not discover new lands without consenting to lose sight of the shore for a very long time.
- Andre Gide