Oh Jiminy Cricket, this is truly delicious! You get hold of some raw, peeled shrimp (as it's a Southern dish, I'm not going to call them prawns), season them with salt and pepper, and fry them briefly in butter, until they turn pink. Personally, I like mine slightly underdone, and the moment they turn, I call it a day. Using a slotted spoon, you take the cooked shrimp out of the pan, leaving the butter behind.
Next, you add a further dollop of butter to the hot pan, let it bubble and in the meantime chop up some fresh tarragon leaves (picked off the stalk) with some spring onions (otherwise known as scallions). Cook these very briefly in the butter.
Deglaze the pan with a slosh of rum (I used Mount Gay- alas, recently re-branded into some awful corporate bottle, but the rum's still the same), flambé to burn off the alcohol, and toss the shrimp back into the pan with the sauce. Bubble for a minute or so, check the seasoning and serve.
The interesting combination of shrimp, butter, rum and tarragon is fabulous.