Grilled Fish with Garlic Beurre Rouge

Beurre rouge is the red-sauced sibling of the classic French beurre blanc, and this version leans hard into Southwestern flavors with green chilies, fresh tomatoes, cilantro, and loads of garlic. It’s spooned over grilled grouper that’s been marinating in olive oil, lemon juice, and slivered garlic.

The sauce builds in layers. Red onion, chilies, and minced garlic sweat in butter until soft, then tomatoes and lemon juice simmer for 10 minutes. Off the heat, you stir in fresh cilantro and the remaining butter in pieces, letting it melt slowly into a rich, glossy, barely emulsified sauce. That off-heat butter incorporation is key. Too much heat breaks the emulsion and you get greasy butter floating on top.

Grill the fish over low, glowing coals and turn it only once. Grouper is firm enough to handle the grill without falling apart, but overcooking dries it out fast. The marinade protects the surface and adds flavor, but the fish itself should be just opaque in the center.

Pro Tips

• Marinate at least one hour, but overnight is better for deeper flavor. The acid in the lemon juice gently seasons the fish all the way through.
• Use a fruity, green olive oil for the marinade. It adds a peppery note that cheap refined oil can’t match.
• Stir the butter into the sauce off the heat, one piece at a time. This creates the silky emulsion that defines a beurre rouge.
• If you don’t have a grill, broiling works well. Keep the fish about 4 inches from the element.

Variations

• Use red snapper, mahi-mahi, or swordfish in place of grouper.
• Swap green chilies for a roasted poblano for smokier, deeper heat.
• Add a splash of white wine to the sauce with the tomatoes for extra acidity and depth.