Coating meats in mustard (Dijon Mustard works best) prior to cooking will impart an amazing depth of flavour.
As simple as painting mustard over every part of the meat and letting sit for 15-20 minutes prior to BBQing or roasting.. You can always add a few herbs into the mustard if you like.
In the above image i have used dijon mustard and rosemary and rubbed it all over some lamb loin chops.