Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   4                    tuna steaks -- (fillets)
                        - approximately 8 oz each
   1      cup           unsalted butter
   2      tablespoons   minced cilantro
   1      teaspoon      jalapeno or serrano chili
                        - peppers -- finely minced
   2      teaspoons     garlic -- finely minced
   1      teaspoon      ginger -- finely minced or
                        - ginger powder

Preparation:

Place softened butter in mixing bowl and beat until fluffy. Blend in the cilantro, chili, garlic, and ginger. Spoon dollops of butter mixture onto waxed paper and refrigerate ahead of time for readied individual servings. Refrigerate. Place fish on rack 3 inches from mesquite coals. Grill fish about 4 to 5 minutes on each side. Place dollops of spiced butter on the finished fillet, or warm the spiced butter and spoon over the cooked steaks. Source: Mesquite Cookery by John 'Boog' Powe