Grilled Whole Flounder with Cajun Garlic Butter (Gas Grill Method)

This weekend’s catch turned into one heck of a simple, flavorful dinner — a 15.5" flounder grilled whole on a basic gas grill. No fancy fish baskets, no foil packets, just a cooling rack and some backyard know-how. If you’ve got a flounder and a few pantry staples, you’re halfway to a meal that tastes like the Gulf Coast.

Step-by-Step: Grilling a Whole Flounder

1. Clean and Score the Fish

To clean the flounder, make a diagonal cut behind the head and gills — when you pull the head, the guts come with it in one easy motion. Rinse well, then scale both sides of the fish. Now take a sharp knife and slice down the lateral line until you hit bone. Add crosshatch cuts across the fillet — this helps the butter and seasoning get deep into the meat.

2. Add Butter and Seasoning

Slice cold butter into small pats and press them deep into each cut on the fish. As it grills, that butter will baste the flounder from the inside out. Sprinkle garlic powder and Cajun seasoning over the top — we used Slap Ya Mama for a spicy Southern kick.

3. Set Up the Grill

You don’t need a fancy smoker — we used a six-burner Monument Grill and ran the outer burners on high, center burners off, for a perfect indirect setup. That cooling rack lets air circulate and keeps flare-ups away from all that butter.

4. Grill to 145°F

Maintain grill temp around 325–350°F. Check after 10 minutes. The butter will melt down into the fish, the skin will start to crisp, and the flesh will turn bright white. We pulled ours at 18 minutes right at 145°F internal — tender, flaky, and full of flavor.

5. Serve It Up

Slide the whole fish onto a plate, maybe serve it with a scoop of seasoned rice or grilled veggies, and enjoy that buttery, spicy flounder straight off the bone. Flakes apart with a fork, just like it should.

Got your own way of grilling fish whole? Drop a comment — we’re always open to new tricks from the backyard pros. Until next time, keep the fire lit and the smoke rollin’! 🔥

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