In a large bowl, whisk the coconut milk, peanut butter, soy sauce, lime juice, brown sugar, garlic, and coriander to make a smooth sauce.

Trim the pork of excess fat and silverskin. Butterfly the tenderloins by splitting each one lengthwise almost but not quite all the way through, so the halves remain attached.

Open each tenderloin like a book, cover with plastic wrap, and pound to an even 1/2-inch thickness with a meat mallet or the bottom of a small skillet. Put the pork tenderloins in the bowl with the marinade and turn to coat. Let marinate for 10 to 20 minutes (or up to several hours in the refrigerator).

While the pork marinates, heat a gas grill with all burners on high. Clean and oil the grate. Remove the tenderloins from themarinade, letting excess marinade drip back into the bowl (don't discard the marinade). Grill the tenderloins, covered, turning once, until just cooked through, 5 to 7 minutes total (cut into one to check). Transfer to a carving board and let rest for 5 minutes.

Meanwhile, pour the marinade into a small saucepan and add 2 tablespoons water; bring to a boil, reduce the heat, and simmer for 3 minutes. Remove from the heat. If the sauce seems too thick, thin it with 1 or 2 teaspoons water. Slice the pork and serve with the sauce on the side.

Serving Suggestions: Serve with steamed jasmine or short-grain rice and stir-fried spinach or snow peas.