In a large saute pan over medium-high heat, add the oil. Put the fish, skin side down, into the pan.
Press firmly with a spatula to prevent the skin from curling. Sear for 3 to 4 minutes, then flip. Add the thyme sprigs, the butter and the lemon juice. Cook for an additional 4 minutes. Baste the fish for 30 seconds. Remove the fish from pan and arrange on a platter to serve.
Cook's Note: Score the skin side of the fish, to prevent it from curling during the cooking.