For the Chimichurri
Mince the garlic in a food processor with the vinegar. Add the remaining ingredients, pulse it down to the consistency you prefer and set aside.
For the Red Snapper
Pat the fish dry inside and out.
Generously salt and pepper the cavity before lining it with lemon slices and rosemary sprigs (gently mash the sprigs to release aroma).
Combine the olive oil with the herb mix in the blender on slow speed until smooth but not emulsified.
Coat both sides of the fish with the herb oil and several pinches of salt and pepper. Place the fish on an oiled grill heated to 425° and cover. (Pro tip: Place the fish down quickly, and do not move it until it’s time to turn it over or it will stick.)
After 5 to 7 minutes, uncover the grill and gently roll the fish over, using the spine as an imaginary hinge, to cook the other side.
Re-cover, and after another 5 to 7 minutes, check the meat in the cavity to see if it looks cooked and flaky. If not, give it a few more minutes.
Plate the fish, generously cover in the mint chimichurri and serve it family-style for a meal that wows.