1/2  cup           olive oil -- green fruity variety
   5      tablespoons   lemon juice -- freshly squeezed
   4      cloves        garlic -- slivered
     1/2  cup           cilantro -- chopped
                        salt and pepper -- to taste
   6      pieces        grouper -- or other firm fish
   4      ounces        butter -- unsalted
     1/4  cup           red onion -- chopped
   2      small         green chili pepper -- finely minced
   1      tablespoon    garlic -- minced
   1      pound         tomatoes -- peeled and chopped
                        lemon wedges and cilantro sprigs
Mix together olive oil, 4 tablespoons lemon juice, slivered garlic, 1/4 cup
cho
pped cilantro, salt and pepper. Add fish fillets and marinate for at least
one 
hour or as long as overnight.
To prepare garlic beurre rouge: In a frying pan over medium heat, melt two
tabl
espoons butter and saute onion, chilies, and minced garlic until soft,
stirring
  often. Add tomatoes and remaining lemon juice. Cook for 10 minutes,
 stirring o
ccasionally. Remove from heat and season to taste. Stir in 1/4 cup chopped
cila
ntro. Slowly stir in remaining butter until melted.
Drain marinade from fish. Barbecue fillets over low glowing coals (or broil
if 
desired), turning only once. Be careful not to overcook. Remove to a warm
servi
ng platter and top with garlic beurre rouge. Garnish with lemon slices and
cila
ntro sprigs.