Step 1

Tear a 2 foot piece of parchment paper and place lemon slices in the middle, lengthwise. Place fresh rosemary and thyme on top of lemon slices. Lay salmon filets on top of herbs. Divide 1 tablespoon of butter among each filet. Fold and seal the parchment paper being careful that the lemon slices and herbs stay on the bottom. Wrap another piece of parchment paper tightly around the fish.

Step 2

Place fish packet into a double boiler for 25 to 30 minutes. While fish is cooking, make the sauce.

Step 3

In a saucepan, combine the remaining 1/4 cup of butter, olive oil, garlic and onion; cook and stir on medium heat for 15 minutes, until onions are transparent. Do not over brown. Pour in heavy cream and cook until it begins to thicken. Remove from the heat.

Step 4

Pour the hot butter mixture into a blender. Add fresh mint and blend on high for 10 to 15 seconds. Pour back into the saucepan to warm and thicken for 2 to 3 minutes, stirring constantly. Do not let it sit too long, or it will begin to break down.

Step 5

When fish is done, remove from parchment paper and pace on a warm plate. Spoon sauce over top of fish.